Guild structure and litterfall production in a mature secondary forest: its implications to silviculture and natural resources management

Professorial Chair Lecture

Mr. and Mrs. Guillermo Ponce Professorial Chair Lecture in Silviculture and Forest Inluences

Place

CFNR Operations Room, UPLB

Date

6-27-2006

Abstract

The contents of this professorial lecture entitled "Guild structure and litterfall production in a mature secondary forest: its implications to silviculture and natural resources management" were the results of the collaborative research project on the 4-Hectare Permanent Ecological Plots in Mt. Makiling between UPLB-CFNR and JIRCAS, Tsukuba, Japan.

The project research site was located in a mature secondary forest near mudspring, Makiling Forest Reserve.

The area was surveyed and gridded into 10 x 10 m plots which subdivided further into 5 x 5 m quadrants.

The trees in the 5 x 5 m quadrants were identified, tagged and mapped out of its distribution in the whole area. Each component tree species were selected based on diameter at breast height and height. All the trees whose diameter at breast height were 5 cm and up and whose height were beyond 5 m in height were included.

The whole area was mapped out topographically and divided into ridge, valley and sloping areas. On the other hand 50 circular litter traps were set-up in the closed stand and 8 traps were established in the gaps/chablis. All the data collected were analyzed for species richness and diversity, diameter classes, topographic preference, crown canopy classes, density, basal area and yearly mortality and growth increment in diameter at breast height.

Results of the study revealed that the mature secondary forest in Mt. Makiling is a complex and diverse forest community composed of forest trees of palms belonging to 44 families, 126 genera and 179 species.

The area has an average density of 192 trees/ha and the average basal area was 43m2/ha. The highest density was obtained by Celtic luzonica (magabuyo), representing 21% of the total number of trees, followed by Diplodiscus paniculatus (balobo), Pinanga insignis (sarawag), Chisocheton cumingianus (balukanag), Ficus congesta (malatibig), Pterocymbium tinctorium (taluto), and Laportea luzonensis (lipa).

The highest dbh was obtained by balete (Ficus balete), binuang (Octomeles sumatrana), haguimit (Ficus minahassae), and bangulo (Litsea garciae). The most dominant species in terms of basal area were balobo, magabuyo and bangulo which gave values of 6.74, 3.36 and 1.51 m2 per ha.

The average height of the forest trees was 11.81m and the tallest trees were Drypetes maguilinginses, Dillenia philippinensis with average height of 21 and 19.6m, respectively. Based on population structure, 17% of the total number of trees were Celtis luzonica (magabuyo) followed by Diplodiscus paniculatus (balobo) and Chisocheton cumingianus (balukanag) which were 8 and 4%, respectively of the total population.

Based on canopy classes, magabuyo was composed of 20%, 13%, and 67% canopy, subcanopy and understories, respectively. Balobo gave values of 42, 19, and 39% respectively for canopy, subcanopy, and understorey crowns, suggesting an older age distribution than magabuyo. Other trees followed the trend of higher populations (50 to 60%) for the understories. Based on mortalities, it was observed that higher values were noted for pugahan (45%), hamindang (42), haguimit (40%) and bangulo (37%). Balobo and magabuyo had mortalities of 12% and 11% respectively.

The fastest growers in terms of dbh increment were binuang (17 mm/year), bangulo (13.81 mm/year), lamog (5.03 mm/year) and magabuyo (2.37 mm/year). Bagtikan had 3.1 mm/year diameter increment.

Seven species were noted to have distributed naturally at the ridge such as balobo, bagtikan, taluto, anuling, bangulo, hamindang and pugahan. Those trees found in the slopes were malak-malak, binuang, apanang and malasaging. On the other hand, balukanag preferred the valley. Many species were found to be generalist and the were magabuyo, kapulasan, tambalau, tinaang pantai, Katong matsing and many others. Canopy trees were magabuyo (13%), balukanag (20%), balobo (47%), taluto (18%) and bagtikan (17%). Other species had values less than 1%. Non canopy forming trees were pugahan, apanang, malasaging, sarawag, malatibig, lipa and katong matsing.

The diversity using the Shannon-Weiner index was 4.72 for trees greater than 5cm in diameter and 4.65 for trees greater than 10cm in diameter, suggesting a moderate value. Gaps constitute 5% of the total area. This ranged from 25 to 275m2. The densiest regenerations were noted for magabuyo (3.33 individuals/m2). Balobo had 1.25 individuals/m2 while bagtikan has 1/m2.

Litter fall production in the area was 15 tons per ha/year and 25% of which was contributed by magabuyo, followed by balobo 18%) and bagtikan (9%). About 65% of the total litter produced were leaves while wood falls, flowers and seeds and trah had values of 19, 4, and 12%, respectively.

In order to enhance succession in the area, it was suggested that the area should be subjected to enriched using the autogenic and allogenic succession principles where shade loving trees should be planted in the natural gaps while intolerant trees should be planted in the chablis. The planting material should be raised following the same principles. It was also suggested that some promising trees in the subcanopy and understory crown levels should be released and be given chance to improve their growth and take the canopy level position.. Crown thinning was likewise suggested. In order to enhance the watershed values of the forest, it was suggested that 3 canopy levels be maintained, the natural and induced gap areas be regenerated and the forest litter be maintained. The understory trees should be maintained for microenvironmental modification and stability.

Location

UPLB Main Library Special Collections Section (USCS)

College

College of Forestry and Natural Resources (CFNR)

Language

English

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