Faculty of Resource Science and Technology Vegetation Structure and Composition of Pioneer Species in Reforestation Area at Gunung Apeng Forest Reserve Cha Hui Kee (26030) Bachelor of Science with Honours (Plant Resource Science and Management) 2013 Vegetation Structure and Composition of Pioneer Species in Reforestation Area at Gunung Apeng Forest Reserve Cha Hui Kee (26030) This project is submitted in partial fulfilment of the requirement for the Degree of Bachelor of Science with Honours (Plant Resource Science and Management) Supervisor: Dr. Mohd. Effendi Wasli Co-supervisor: Prof. Dr. Hamsawi Sani Plant Resource Science and Management Programme Department of Plant Science and Environmental Ecology Faculty of Resource Science and Technology Universiti Malaysia Sarawak 2013 I APPROVAL SHEET Name of candidate : Cha Hui Kee Title of dissertation : Vegetation Structure and Composition of Pioneer Species in Reforestation Area at Gunung Apeng Forest Reserve Dr. Mohd. Effendi Wasli Supervisor Dr. Rebicca Edward Coordinator Plant Resource Science and Management Programme Department of Plant Science and Environmental Ecology Faculty of Resource Science and Technology II DECLARATION I hereby declare that this Final Year Project Report 2013 is based on my own work besides the citations and quotations that had been acknowledged. And also to declare that it has not been submitted to any other degree of qualification at Universiti Malaysia Sarawak (UNIMAS) or other institution of higher learning. CHA HUI KEE Plant Resource Science and Management Programme Department of Plant Science and Environment Ecology Faculty of Resource Science and Technology Universiti Malaysia Sarawak III ACKNOWLEDGEMENT First of all, I would like to thank God for giving me the strength and health to finish my final year project. After that, I would like to express my deepest gratitude to Dr. Mohd. Effendi b. Wasli, my research supervisor, for his patient guidance and constructive suggestions on this research project. The time and effort he spent into guiding me for this research project is very much appreciated. I am also grateful to have my co-supervisor, Prof. Hamsawi Sani, who too guided me during my research study. The assistances given by lecturers and staffs of the Faculty of Resource Science and Technology (FSTS) were greatly appreciated. I wish to specially thank Mr. Hidir Marzuki, technical staff of the FSTS, for his help on plant species identification. Next, I wish to acknowledge the help given by the supporting staffs from Gunung Apeng Forest Reserve who patiently helped me with my data collection and species identification. I would also like to offer my appreciation to my family, which includes my parents, Mr. Cha Chew Ching and Mrs. Sum Kam Liang; and my siblings, Cha Wai Yip and Cha Hong Yip, for all their mental supports during the research study. Not to forget, many thanks to my friends and seniors who helped out and supported me during the completion of my research. I wish to specially thank my research partner, Ms. Lee Pick Sean, for helping me out with my data collection and always supporting me. And last but not least, I would like to thank the Faculty of Resource Science and Technology (FRST), Universiti Malaysia Sarawak, for giving me the opportunity to conduct this research. IV Vegetation Structure and Composition of Pioneer Species in Reforestation Area at Gunung Apeng Forest Reserve Cha Hui Kee Plant Resource Science and Management Faculty of Resource Science and Technology Universiti Malaysia Sarawak ABSTRACT This study was cconducted to collect information on the vegetation structure and composition of pioneer species in reforestation area at Gunung Apeng Forest Reserve that was artificially planted with Dipterocarp species Dryobalanops beccarii. There were two study sites constructed, namely R05 located in a reforestation area established in year 2005, and R07 in a reforestation area established in year 2007. The data collected and analyzed were height, diameter breast height (dbh), species name, plant group, and number of occurrence of each species. Comparison in terms of species diversity and evenness between the study plots were determined using Shannon-Wiener Diversity Index and Species Evenness Index. In both R05 and R07 study sites, the plant group with the highest number of species is tree, followed by climber, fern, and shrub. The density of undergrowth species is higher than the density of tree species in R05 and R07. In study site R05, Rubiaceae family has the highest number of plant species, while Rubiaceae family and Moraceae family are the two families that have the highest number of plant species in R07. Pioneer tree species in R05 was dominated by Macaranga gigantea, while most pioneer tree species encountered in R07 were Commersonia spp. Diversity and evenness indexes showed that study site R05 has higher and more even plant diversity distribution than R07. The vegetation structure and composition of pioneer species in reforestation area is important in determining the current regeneration condition of the forest, and it is also an important reference for future forest management activity. Key words: Reforestation, vegetation survey, tree crown distribution, pioneer species, Gunung Apeng. ABSTRAK Kajian ini dijalankan untuk mengumpul maklumat tentang struktur and komposisi spesies perintis di dalam kawasan penghutanan semula di Hutan Simpan Gunung Apeng yang telah ditanam dengan spesies Dipterocarp Drobalanops beccarii. Dua kawasan kajian telah dikonstruk, iaitu R05 yang terletak dalam kawasan penghutanan semula yang ditubuhkan pada tahun 2005, dan R07 terletak dalam kawasan penghutanan semula yang ditubuhkan pada tahun 2007. Jenis data yang telah dikumpul dan dianalisis ialah ketinggian, diameter perepang paras dada, nama species, kumpulan tumbuhan, dan jumlah setiap species yang dijumpai. Indeks Kepelbagaian Shannon-Wiener dan Indeks Kesamarataan Species telah digunakan untuk membandingkan kepelbagaian dan persamaan spesies. Dalam kedua-dua kawasan kajian R05 dan R07, kumpulan tumbuhan yang mempunyai spesies yang paling banyak ialah kumpulan pokok, diikuti dengan tumbuhan menjalar, paku-pakis, dan pokok renek. Kepadatan tumbuhan kategori semak adalah lebih tinggi berbanding dengan kepadatan spesies pokok dalam R05 dan R07. Rubiaceae mempunyai spesies tumbuhan yang paling banyak dalam kawasan kajian R05, manakala Moraceae dan Rubiaceae mempunyai spesies tumbuhan yang paling banyak dalam R07. Spesies pokok perisntis dalam R05 didominasi oleh Macaranga gigantea, manakala kebanyakan pokok perintis dalam kawasan kajian R07 merupakan Commersonia spp. Indeks kepelbagaian dan kesamarataan menunjukkan bahawa taburan spesies tumbuhan di R05 mempunyai kepelbagaian dan kesamarataan yang lebih tinggi berbanding dengan kawasan penghutanan semula R07. Maklumat tentang struktur dan komposisi spesies perintis adalah penting untuk mengetahui keadaan pertumbuhan semula hutan, dan maklumat tersebut juga boleh digunakan sebagai rujukan untuk aktiviti pengurusan hutan. Kata kunci: Penghutanan semula, kajian tunbuh-tumbuhan, taburan silara pokok, spesies perintis, Gunung Apeng. V TABLE OF CONTENTS PAGE NO. Title Page .............................................................................................................................. I Approval Sheet ................................................................................................................... II Declaration ........................................................................................................................ III Acknowledgement ............................................................................................................. IV Abstract .............................................................................................................................. V Table of Contents .............................................................................................................. VI List of Abbreviations ..................................................................................................... VIII List of Tables and Figures ............................................................................................... IX 1.0 Introduction .................................................................................................................. 1 2.0 Literature Review ......................................................................................................... 4 2.1 Tropical Rain Forest .................................................................................................... 4 2.2 Forest in Sarawak and Its Importance .......................................................................... 4 2.3 Threats of Sarawak Forests .......................................................................................... 5 2.4 Secondary Forests ........................................................................................................ 6 2.5 Rehabilitation of Secondary Forests ............................................................................ 8 2.6 Previous Studies on Secondary Forests Vegetation and Dynamics after Various Form of Disturbance .................................................................................................................... 9 2.6.1 Indonesia ............................................................................................................... 9 2.6.2 India .................................................................................................................... 10 2.6.3 Sri Lanka ............................................................................................................. 11 VI 2.6.4 Thailand............................................................................................................... 13 2.6.5 Himalaya: North-Eastern Hill Region of India ................................................... 14 2.6.6 Malaysia .............................................................................................................. 14 3.0 Materials and Methods .............................................................................................. 16 3.1 Study Area ................................................................................................................. 16 3.2 Sampling Design ........................................................................................................ 18 3.3 Data Collection .......................................................................................................... 18 3.4 Shannon-Wiener Diversity Index (H’) and Species Evenness Index ........................ 20 4.0 Results and Discussion ............................................................................................... 22 4.1 Vegetation Composition of Plant Species within R05 and R07 ................................ 22 4.2 Shanon-Wiener Diversity and Evenness Indexes for All Species ............................. 25 4.3 Composition and Structure of Tree Species with dbh of 10cm or more in R05 ........ 26 4.4 Composition and Structure of Tree Species with dbh of 10cm or more in R07 ........ 32 4.5 Shanon-Wiener Diversity and Evenness Indexes for Tree Species with dbh of 10cm or more ............................................................................................................................. 37 4.6 Plant Composition and Structure on Forest Regeneration Condition and Silviculture .......................................................................................................................................... 39 5.0 Conclusion and Recommendations ............................................................................ 42 References ......................................................................................................................... 44 Appendix ........................................................................................................................... 49 VII LIST OF ABBREVIATIONS cm – Centimeter dbh – Diameter at breast height m – Meter m2 – Meter squared (m×m) mm – Millimeter PFE – Permanent Forest Estate sp. – Species spp. – Several species TPAs – Totally Protected Areas VIII LIST OF TABLES AND FIGURES Tables Table Content Page 1 Dipterocarps recommended for planting in Malaysia and Indonesia……. 9 2 Regeneration of natural species in man-made plantations in the Panchmahal district of Gujarat state and the Uttara Kannada district in the Western Ghats of Karnataka state compared with the total species composition of natural forests of the Valsad area of Gujarat. All values indicate the number of species per hectare………………………………. 10 3 4 Natural regeneration in 6-years-old JFM mixed-species plantations in the Uttara Kannada district, Western Ghats, South India………………................................................................................. 11 Similarity of species before and immediately after shifting cultivation at Sigiriya area in the dry zone of Sri Lanka. Dominant species and families which composed 75% of the vegetation are given in descending order of abundance. Species and families found in both before and after shifting cultivation are underlined……………………………………………….. 12 Common plant associations in dry deciduous secondary forests……………………………………………………………………. 12 6 Plant groups that were recorded in R05 and R07…................................. 22 7 Shannon – Wiener Diversity Index and Species Evenness Index of all species in R05 and R07………………………………………………….. 25 Shannon – Wiener Diversity Index and Species Evenness Index of tree species in R05 and R07……………………………................................ 37 Dbh measurement of tree species encountered in R05 with dbh ≥ 10 cm ……………………………...................................................................... 49 Height measurement of tree species encountered in R05 with dbh ≥ 10 cm............................................................................................................ 51 Dbh measurement of tree species encountered in R07 with dbh ≥ 10 cm …………………………….................................................................... 53 Height measurement of tree species encountered in R07 with dbh ≥ 10 cm ……………………………………………………………………… 54 List of plant species encountered in R05………………………………. 56 5 8 9 10 11 12 13 IX 14 List of plant species encountered in R07…........................................... 59 Figures Figure Content Page 1 Location map of Gunung Apeng Forest Reserve……….…………….. 16 2 Gunung Apeng Forest Reserve in year 2007…………………………… 16 3 Log-transformed plant density by plant groups in R05 and R07……………………………………………………………………… 24 Tree crowns structure of tree species in R05 with dbh ≥ 10 cm ………………………………………………………………………. 27 Diameter distribution of pioneer tree species in R05 with dbh ≥ 10 cm........................................................................................................... 30 Height distribution of pioneer tree species in R05 with dbh ≥ 10 cm........................................................................................................... 31 Tree crowns structure of tree species in R07 tree dbh ≥ 10 cm ………………………………………………………………………. 33 Diameter distribution of tree species in R07 with dbh ≥ 10 cm ………………………………………………………………………. 35 Height distribution of tree species in R07 with dbh ≥ 10 cm………………………………………………………………………. 36 4 5 6 7 8 9 X 1.0 INTRODUCTION Rainforests are forests that grow in parts of the world where the forest would receive a lot of rainfall. It receives rain consistently throughout the year, rather than just heavy rain in certain time of the year. Generally, there are two common types of rain forest, which are the temperate rain forests and the tropical rain forests. Temperate rain forests are found in places such as North America’s northwest coast, on the South Island of New Zealand, and in southern Chile (Champion, 2007). For Malaysia and a few other countries along the equator, our forests are covered by the tropical rain forests. Tropical rain forests are known for its rich biodiversity, which includes many species of plants, animals and other living organisms. In 1 hectare of rain forest, we can find between 50 to 200 different types of tree species, which is 20 times the species that can be found in temperate forests (Champion, 2007). This shows the importance of rain forest as a habitat to numerous living organisms on earth. But, some of the forests in Malaysia are destructed, mainly by human activities such as logging and shifting cultivation. After the forest is destructed, it is usually left to regenerate, and the regenerated forest is known as secondary forest. According to Brown and Lugo (1990), tropical secondary forests are forests formed after the occurrence of human impact on forest lands. The forest regenerates largely by natural processes after experiencing disturbance or destruction of the original forest vegetation. The vegetation of the secondary forest has a major difference as compared to the primary forest in terms of canopy species composition and forest structure. It usually contains much lower biodiversity compared to the original forest (Raffles Museum of Biodiversity Research [RMBR], 2012). It is unlikely for secondary forest to return to a 1 pristine forest in a short time, unless it is protected from further exploitation for a century or more (Odera, 2002). In order to restore the disturbed forest area at a faster pace, one option to recover the depleted forest is thru reforestation. Reforestation is the replanting of trees on forest areas which was disturbed by human activities or natural means (Hine & Martin, 2004). Unlike the function of replanting of exotic or fast growing timber species for supplying material for timber and wood products, reforestation is applied mainly for conserving the natural forest ecosystem and at the same time mitigates climate change. One example of important environmental services provided by forests is to act as an agent in ameliorating greenhouse gases in the atmosphere thru carbon sinking properties. Reforestation can help in protecting the biodiversity of the forest, which may include many valuable plant or animal species. The success of reforestation depends on a lot of factors, and one of it being the interactions between the planted trees and the secondary forest’s pioneer species. Pioneer species are species of trees or plants that colonize the forest land after a disturbance, and they are usually fast-growing, shade intolerant and short–lived. Pioneer species include woody and herbaceous (non-woody) species, because there are certain herbaceous species that are able to colonise disturbed land. In Mediterranean, pioneer herbaceous legumes with hard-coated seeds are usually among the early post-fire colonizers (Arianautsou & Thanos, 1996). Some possible interactions would be competing for light, nutrients and water. But, the pioneer species might also help in forest restoration. One type of helpful pioneer species would be the soil enrichers. The soil enrichers will improve the degraded secondary forest soil by enriching the soils with nutrients such as nitrogen, and their leaf litter will increase the humus content of the soil. 2 Reforestation will involve human intervention and also artificial planting of trees. The problem with reforestation is that the artificially planted trees might not grow well, or even die because they might face competition from the pioneer species. Pioneer species are the type of fast growing plant that dominates the forest in secondary forest. The species diversity and structure of reforestation area can be used as a reference as whether further silvicultural treatment needed in the reforestation area. Species diversity of naturally existing plant species is vital in understanding the interaction between the naturally existing plant species with the growth of planted indigenous tree species for reforestation purpose in the area. Also by performing studies on the pioneer species, we can find out the regeneration status of a reforestation area. The study was carried out to determine the composition and structure of pioneer species in two different reforestation areas of different ages that was located in Gunung Apeng Forest Reserve. The data collected can be used as a reference for future sivilculture activites, and it also can be used to find out the regeneration state of the reforestation area. 3 2.0 LITERATURE REVIEW 2.1 Tropical Rain Forest Tropical rain forests are tall, dense, evergreen forests that are formed in wet tropics, which receives consistent rain fall, have hot climates, and have short or absent dry seasons (Corlett & Primack, 2011). They can be found in regions which are near to or on the earth’s equator, such as Central and South America, Africa, Asia, and Australia (Champion, 2007). Malaysia is one of the countries in Asia that have tropical rain forests. There is a very rich diversity of plant species that can be found in tropical rain forests as compared to temperate forests which have lesser plant diversity. Most of the rainforest trees are evergreen, and have broad leaves. The forests are crowded with all kinds of plants, from small shrubs to big trees. In order to compete for sunlight, trees in tropical rain forests can grow enormously high, often reaching 60-90cm (Champion, 2007). Because of the persistent rain and the abundant sunlight, the plants in tropical rain forests are always in growing seasons. Their growth continues all year long. This is different from temperate forests that have seasonal change. During winter, the leaves of trees in temperate forests will fall off, and living organisms goes into hibernation. This does not happen in tropical rain forest. 2.2 The Importance of Tropical Rainforest in Sarawak Currently, there are approximately 12.4 million ha of land area in Sarawak (Forest Department of Sarawak, 2012). According to the Forest Department of Sarawak (2012), it is estimated that 65% of the land area are still occupied by forest. The amount of forested area has decreased throughout the last 50 years due to natural and human activities such as commercial logging, shifting cultivation, and agriculture. The Sarawak Government has set 4 six million ha of production forest as Permanent Forest Estate (PFE) for sustainable timber production (Forest Department of Sarawak, 2012). There is also one million ha of land classified as Totally Protected Areas (TPAs), which includes national park, wildlife sanctuaries, and nature reserves (Forest Department of Sarawak, 2012). Without a doubt, tropical rainforest is rich in biodiversity and is a habitat for various types of animals and plants. Besides the animals, we can also find a lot of timbers and non-timber products in Sarawak forests. Some examples of timber species available in Sarawak forests are Shorea (meranti), Dipterocarps (keruing) and Dryobalanops. One example of non-timber products found in Sarawak forest is rattan. Rattan is widely used in furniture making, and also to make smaller items such as baskets. The second importance of forest is that they provide environmental services and help to regulate our environment. Rain forests are known as carbon sink, because they absorb carbon dioxide in the atmosphere, and produce oxygen which are needed by animals. Tropical rain forests also act as a water reservoir. They store water in the soil, and later released back the water into the environment. In Sarawak, there are still many indigenous people and local communities who rely on the rain forests in their daily life. They live in or nearby the forests, earn their living by collecting forest products, and also use forest lands for farming or shifting cultivation. For example, the Penan people survive by hunting animals and collecting resources from the forest. 2.3 Threats of Sarawak Forests Nowadays, due to events such as natural phenomena and human activities, the area of forested land in Sarawak is decreasing through time. We can divide the possible causes 5 of deforestation into three main groups, which are agricultural expansion, wood extraction, and infrastructure extension (Geist & Lambin, 2007). For Sarawak, possible agricultural practices that lead to deforestation would be shifting cultivation and permanent cultivation. For shifting cultivation, the indigenous farmers will clear a forest area by slash and burn technique, uses the area for cultivation, and later leaves the area after harvesting so that it will regenerate. For permanent cultivation, an area of land is cleared in order to be used for long period cultivation. The second cause is wood extraction. As mentioned above, a lot of valuable timber species can be found in Sarawak forests. These commercial woods are then logged by timber companies to be sold. Wood in the forest may also be extracted for fuel wood and charcoal production. The third cause of deforestation is infrastructure extension. Since Malaysia is a developing country, we are continuously building new infrastructures. In order to make space for these infrastructures, we have to clear some forests and use the forest land for construction. 2.4 Secondary Forests According to Chokkalingam, De Jong, Smith, & Sabogal (2000), secondary forests are “forests regenerating largely through natural processes after significant human disturbance of the original forest vegetation at a single point in time or over an extended period, and displaying a major difference in forest structure and/or canopy species composition with respect to nearby primary forests on similar sites”. Secondary forests is generally unstable and having successional stages. 6 Odera (2002) divided secondary forests into five different groups, which are post extraction secondary forests, swidden fallow secondary forests, rehabilitated secondary forests, post-fire secondary forests, and post-abandonment secondary forests. Post extraction secondary forests are forests regenerating largely through natural processes after significant reduction in forest vegetation through tree extraction in a single time or over an extended period, and there are major changes in the forest structure and species. Swidden fallow secondary forests are forests regenerating mainly by natural processes in woody fallows of swidden agriculture for the purpose of food production by farmers and/or community. Rehabilitated secondary forests are forests that regenerate mainly by natural processes on degraded area. The regeneration process could be facilitated by protection from chronic disturbance, site stabilization, water management and enrichment planting. A post-fire secondary forest is a forest regenerating mainly by natural processes after a reduction in primary forest vegetation caused by forest fires. Lastly, a post-abandonment secondary forest is a forest regenerating largely through natural processes after land used for agriculture and pasture development were abandoned. In the succession process of secondary forest, there are two crude categories of species, which are the pioneer species and the climax species (Swaine & Whitmore, 1988). Pioneer species are the types of plants that germinate, establish, grow and mature very quickly in the clearings and breaks created after the death of dominant plants. Pioneer species only grow in highly disturbed area. They will exploit the resources made available by the death of dominant plants. The early pioneer species are often fastgrowing, short lived weedy trees. Their seeds are able to germinate in in the dark understory of forests, and the seedlings are shade-tolerant for a long period. When forest disturbance occur, the pioneer species have more light and food resources, thus it increase in growth. 7 2.5 Rehabilitation of Secondary Forest Forest rehabilitation is human intervention to counter forest degradation processes, such as to promote forest recovery in large gaps of Dipterocarp forest, or the conversion of shrub forest to high story plantation forest (Mori, n.d.). Forest rehabilitation will maximize forest function in order to satisfy human aims. One of the methods used for the rehabilitation of secondary forest is enrichment planting. Enrichment planting is an effective method in rehabilitating degraded tropical forests, especially with the use of indigenous tree species that is beneficial such as timber, tree species that can provide food, and tree species that have medical values, in Southeast Asia (Appanah & Weinland, 1993; Ådjers et al. 1995; Lamb et al., 2005). Matsumoto et al. (2011) reported that the rate of growth and survival of planted seedlings of indigenous tree species namely Dyera costulata (Miq.) Hook.f., Dipterocarpus baudii Korth, Neobalanocarpus heimii (King) Ashton and Gonystylus affinis Radlk are different among species even though they belong in the same taxonomic group. The growth and photosynthesis of D. costulata and Dipt. baudii were maximized at 30-40% canopy openness, and may be suitable for planting under large canopy gaps unlike G. affinis and N. heimii. Thus, G. affinis and N. heimii are more suitable to be planted under small gap opening and low light condition. In order to improve enrichment planting, species-specific ecological traits, especially adaptation and growth performance for light condition need to be considered. Mori (n.d.) conducted a study in East Kalimantan, Indonesia to find out suitable rehabilitation methods for the restoration of Dipterocarp forest. Two important aspects for rehabilitation using Dipterocarp species is light control and species choice. The light requirements and growing stages of species should be taken into consideration. We can 8 control the light intensity using the pre-existing trees or fast-growing trees. One of the problems of single Dipterocarp species stand is the irregularity of seed production. It is recommended to perform mixed planting with other climax species, even though more study is needed. Table 1 below shows the Dipterocarps recommended for planting in Malaysia and Indonesia as proposed by Ishida et al. (2000). Table 1: Dipterocarps recommended for planting in Malaysia and Indonesia. For combination planting on grassland in Indonesia Species Anisoptera marginata Hopea sangal Shorea leprosula Vatica sp. For enrichment planting in Peninsula Malaysia Species Anisoptera laevis Hopea odorata A. scalphuta Shorea acuminata Dipterocarpus baudii S. leprosula D. costulatus S. macroptera D. kerrii S. ovalis Dryobalanops aromatica S. parvifolia D. oblongifolia S. platyclados Sources: Ishida et al. (2000) and Mori et al. (1990). 2.6 Previous Studies on Secondary Forests Vegetation and Dynamics after Various Form of Disturbance 2.6.1 Indonesia In Indonesia, selective logging causes the forest to form large canopy opening (Kartawinata et al., 2001). These canopy openings are then invaded by light-demanding, fast-growing and light-wood pioneer species. Only a few of the species have commercial timber value. The remaining undesirable trees left after logging will provide seeds for the future crop. This makes the future crops undesirable, smaller and genetically inferior (Blanche, 1978; Ashton, 1980). Climbers invade the bare grounds and supress the growth of the residual trees (Kartawinata et al, 2001). The number of tree species in postextraction secondary forest is lower compare to primary forest, but the standing stock is higher and the nucleus trees are sufficient for future development of the forest (Gintings, 1969; Tarumingkeng et al., 1989). The seedlings of certain timber species such as Shorea 9 leprosula and Dryobalanops lanceolata grow faster in secondary forest of different ages than in primary forest, and they grow fastest in 1-year-old secondary forest (Howlett & Davidson 1996, Oorschot et al., 1996). However, Dipterocarpus spp. and Agathis damara show slower growth in secondary forest (Oorschot et al, 1996). 2.6.2 India The social afforestation programmes in India was dominated by monocultures of exotic species, such as Acacia auriculiformis, Acacia mangium, Eucalyptus spp., and Casuarina spp. (Bhat, et al, 2001). The teak plantations in the Panchmahal district of Gujarat state show natural regeneration and the pattern of regeneration was comparable to that of natural forests in the Valsad area of that state (Shah, 1996). Other studies in the Uttara Kannada district in the Western Ghats region of the state of Karnataka in south India also showed that the natural regeneration of species in the plantation is good and similar to that in natural forests (Bhat et al, 2001). Table 2 below shows the comparison of vegetation between several natural forest and plantation forests in India. Table 2: Regeneration of natural species in man-made plantations in the Panchmahal district of Gujarat state and the Uttara Kannada district in the Western Ghats of Karnataka state compared with the total species composition of natural forests of the Valsad area of Gujarat. All values indicate the number of species per hectare. Life forms Teak plantation in Panchmahal1 Natural forest in Valsad1 Tree species 88 Shrub and herb 19 species Climber species 14 Grass species 16 Total species 137 Sources: 1Shah (1996) and 2Bhat et. al. (1984). 67 17 17 9 110 10 Eucalyptus plantation in Uttara Kannada2 25 11+7 Teak plantation in Uttara Kannada2 1 2 44 44 24 10+8 The plantations in Uttara Kannada district are dominated by monocultures of exotic species (Bhat et al, 2001). However, protections were given to the reforested areas in the initial years, and it has promoted the regeneration of naturally occurring species (Bhat et al., 2001). Table 3 shows the study in Uttara Kannada, in which significant natural regeneration was observed under 6-y-old Joint Forest Management (JFM) plantations. Table 3: Natural regeneration in 6-years-old JFM mixed-species plantations in the Uttara Kannada district, Western Ghats, South India. Village Kalgadde Nidgod Illumane HukliShiavlmane Hulibailu Total density tree ha-1 Species planted 2003 1274 1708 1900 No. of species ha-1 5 10 12 11 Tree density ha-1 1455 1071 1658 1630 1545 6 1473 Species naturally regenerating No. of Tree density -1 species ha ha-1 21 548 22 197 20 50 28 270 12 72 Source: Bhat et al., 2001 2.6.3 Sri Lanka Most forests in Sri Lanka are secondary forests that are formed from swidden agriculture. After the swidden field were abandon, the forest regenerates almost entirely by vegetative regrowth rather than from seeds. This makes the secondary forest vegetation very similar to the plant species existed prior to cultivation (Table 4). The young secondary forests consist of mostly pioneer species that can reproduce from root suckers. A study conducted in Sigiriya, Sri Lanka shows that 67% of the species and 57% of the individuals that grow out immediately after swidden farming are early and late seral species (Perera, 1998). Also, at different ages of the forest, there are different plant associations (Table 5). 11 Table 4: Similarity of species before and immediately after shifting cultivation at Sigiriya area in the dry zone of Sri Lanka. Dominant species and families which composed 75% of the vegetation are given in descending order of abundance. Species and families found in both before and after shifting cultivation are underlined. Value of Sorenson coefficient 0.759 ± 0.106 Dominant species Dominant families Before shifting cultivation (12-15 year old secondary forest) Chramolama odorata Pterospermum suberifolium Securinega leucopvrus Catunaregam spinosa Toddalia asiatica Lantana camara Greuiia damine Mallatus philippensis Zaiphus oenoplia Solatia oblonga After shifting cultivation month old fallow forest) Pterospermum suberifolium Securinega leucopyrus Chromolaena odorata Grewia arientati Mallatus philippensis Grewia damine Catunaregam spinosa Toddalia asiatica Euphorbiaceae Asteraceae Sterculiaceae Rutaceae Verbenaceae Rubiaceae Leguminosae Euphorbiaceae Sterculiaceae Tiliaceae Asteraceae (1 Source: Perera, 1998 Table 5: Common plant associations in dry deciduous secondary forests. Age of forest >3 years Plant associations Many re-sprouted individuals 4-11 years Phyllanthus polyphyllus -Croton laccifer - Catunaregam spinosa* Securinega leucopyrus* 12-17 years Ziziphus oenoplia* - Lantana camara* - Catunaregam spinosa* Securinega leucopyrus* Grewia spp. - Pterospermum suberifolium - Premna spp. Walsura trifoliolata ~18 years to old growth forest *Shrubs with thorns or prickles. 12 Other characteristics Many agricultural weed and grass species grow. The soil is exposed to direct sunlight. Pseudo-canopy appears. Individuals have many stems. Croton laccifer grows well in somewhat shady/moist places (Dittus, 1977). Thorny shrub species dominate the land. Tree species dominate the forest. At early stage, the species diversity in dry deciduous regenerating forest increases with succession. But at later stage, the species diversity decreases slightly. According to Perera (1998), the species diversity is high in 20-25 years old forests, but low in old growth forests. This finding agrees with the researches done by Cornell (1987) and Swaine & Hall (1983) in the humid tropics, which is that forests in mid-successional stages have high species and habitat diversities. Also, the diversity of plant family is lower in young fallow forest, as compared to higher species diversity in mature swidden fallow secondary forests (Perera, 2001). 2.6.4 Thailand In secondary forest, most of the trees have small diameter, which results in high density (1600 to 2000 trees ha-1) and low basal area (28 m2 ha-1) (Schmidt-Vogt, 2001). Many tree species in secondary forests form high and narrow crowns to obtain more light (Boojh & Ramakrishnan, 1982). There are more than 30 species per 500 m2 in the tree layer of the most species-rich swidden fallow secondary forest stands (Schmidt-Vogt, 2001). The most important species are Schima wattichii and Eurya acuminata (Theaceae), Castanopsis armata, Lithocarpus elegans and Quercus spp. (Fagaceae), Aporusa wallichii, A. vittosa and Glochidion sphaerogynum (Euphorbiaceae), and Styrax benzoides (Styracaceae) (Schmidt-Vogt, 2001). The families Leguminosae, Lauraceae, Anacardiaceae, Ebenaceae, Rubiaceae, Myrsinaceae and Caprifoliaceae are represented by the highest number of species (Schmidt-Vogt, 2001). 13
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