Volume 16 Nos. 1 & 2
Chemical changes in
microbially infected forest tree seeds
Chemical changes in
microbially infected seeds of seven forest tree species, three artificially
inoculated and four naturally infected seeds were studied to determine the
effect of microfungi on the food reserves of seeds such as starch, total sugar,
and fat.
Chemical analysis
showed significant reduction in total sugar content of all species, both the
artificially inoculated and healthy seed samples. A decrease in starch content
was observed on mahogany seeds inoculated with Fusarium moniliforme, F.
solani and Lasiodiplodia theobromae; and Ldtheobromae; and
kakawate with Ldtheobromae. For the fat content, the same results were
observed except on ipil which had an increase. Insignificant changes in starch
content were noted on narra seeds infected with C. gloeosporioides, Phoma sp.
and F. moniliforme; and raintree seeds with F. solani comparable
with the healthy samples. The changes in ion content, Ca, Mg, P and K of raintree,
mahogany, narra and ipil seeds infected with various fungi cited above were
insignificant as compared with the healthy seeds, decreased in bagtikan and
increased in dagang seeds.
The presence of
Microfungi on forest tree seeds not only affects the quality of the seedlot but
also the morphological as well as the anatomical structures and the chemical
components of the seeds.
Seeds contain
principaly three major chemical components or food reserves, namely:
carbohydrates, fats and oils, and proteins. Carbohydrates are universally found
in living tissues and are very important for metabolic processes. They also
provide the main structural component of plant tissue which is divided into two
main groups, the polysaccharides including starch and monosaccharides including
simple sugar. In cereals, oils are stored within the scutellum, while proteins
are stored in the cotyledons and endosperm.
During seed
germination, these stored food reserves undergo chemical changes so that they
can be used in the different processes inside the seeds and hence seedling
development begins. This is true in healthy and normal seeds. But what will
happen to starch, sugar, fat and ion contents of the seeds when seeds become
infected with pathogenic microfungi? Will there be an increase or reduction in
their chemical components? What will be the effect of a specific fungus on the
chemical components of the seeds? Will it affect seed germinability? Hence,
this study.
Identification of
important wood-decaying fungi associated with some Philippine dipterocarps at
the Makiling forest
Field survey and
laboratory experiment were conducted sequentially from May 2003 to January
2005. The study areas were the Dipterocarp Forest and Plantation, Makiling
Botanical Garden, ERDB Experiment Station and the UP College of Forestry and
Natural Resources campus at the Mt. Makiling Forest Reserve.
There were 27 species
of Basidiomycetes belonging to 15 genera, i.e., Ganoderma, Polystictus,
Auricularia, Phellinus, Polyporus, Fomes, Stereum, Poria, Daedalea, Hexagona,
Lenzites, Hymenochaete, Trametes, Schizophyllum, and Corticum collected. These
were characterized morphologically and anatomically prior to identification.
The Ganoderma, Polystictus, Auricularia, Fomes and Polyporus were represented
by species dominating the area. Among the dipterocarp host species, white lauan
(Shorea contorta Vid.) had the widest range of fungal association.
Wood decay is a common
occurence among all kinds of trees. Decay can affect the sapwood, or heartwood
of a tree. This has been observed in dying trees or in trees which have smaller
leaves and slower growth. In many dipterocarps, the decay losses caused by
basidiomycetous fungi are enormous.
There are are two
types of wood decay caused by basidiomycetous fungi. These are the white and
brown rot. This type of decay can be distinguished by the color of the decayed
wood. The white rot decomposes all components of the wood including lignin. The
decomposed wood is white, and sometimes yellow, tan or even light brown in
color and zone lines are present. The brown rot decomposes the cellulose and
its associated pentosans leaving the lignin more or less unaffected. The
decomposed wood is usually dark brown and without zone lines.
Effect of detopping
and bending on the production of orthotropic shoots for vegetative propagation
of palosapis [Anisoptera thurifera (Blanco) Blume]
The following
rejuvenation methods were used to induce production of orthotropic shoots by
reiteration: 1) detopping/hedging only at 1 m height; and 2) detopping at 1 m
and bending. It was found that combined hedging/detopping and bending (method
2) or the manipulation of the orientation of stems from vertical to horizontal
increased the ability of the species to produce more orthotropic shoots due to
the increased ability to capture more light compared to detopping/decapitation
alone.
Palosapis (A.
thurifera) was found to have weak apical dominance because its stockplants were
capable of producing multiple shoots per harvest cycle.
Economic valuation of
grassland degradation under different pasture classifications
Two valuation
approaches for grassland degradation, namely, Production Function Approach
(Based on forage production) and Process-Response Approach (based on
erosion-induced lost productivity) were used in this study. Lost animal
production was computed, based on what the difference in herbage yield between
degraded pasture and non-degraded pasture could have supported, given an
average herbage consumption of 25,000 kg/animal/year. The SCUAF model was used
to predict the effects of changes in grazing practices on soil erosion over a
10-year period. Valuation approach using forage production closely reveals the
actual rate and costs of degradation
Litterfall production
in a natural mangrove forest in Davila, Pasuquin, Ilocos Norte
The study was
undertaken to assess the monthly litterfall production of mixed mangrove
species in Davila, Pasuquin, Ilocos Norte from May 2000 to April 2001. Two
litter trays (1m x 1m) made of plastic mesh net were installed in each 15m x
15m experimental plot randomly laid-out within the mangrove forest. The trays
were installed 0.5m from the forest floor to eliminate intrusion eliminate
intrusion of other debris in the ground. Litter collection was done monthly
from May 2000 to April 2001. Fresh litter from each tray were put into paper
bags, properly labelled and dried at 70C0 in the oven for one week before
final weight measurements were made. One kg composite soil samples, collected
at the start and end of the study, were analyzed at the Department of Agriculture
Regional Soils Laboratory.
A total of 11 species
were recorded from the experimental plots. The mangrove species in the study
site is dominated by malatangal (Ceriops decandra) with importance value of
22.32%, followed by bakauan babae (Rhizophora mucronata), with importance value
of 21.97%. The least dominant are tabao (Lumnitzera littorea), buta-buta (Excoecaria
agallocha) and putat (Barringtonia racemosa roxb.) with importance value
of 1.97%.
Findings showed that
the highest litterfall production of 1,506 kg/ha was observed in July followed
by 1,398.5 kg/ha in June. The lowest was recorded in February with a litterfall
production of 129.66 kg/ha.
Litterfall production
is strongly correlated with rainfall and relative humidity with coefficient values
of 0.6503 and 0.6369, respectively. This implies that the higher the rainfall,
the higher is the litterfall.
Survival and growth
response of selected reforestation seedlings to pure and mixed sludge media
Seedlings of Eucalyptus
deglupta Blume, Triplaris cumingiana Fisch. and Mey., Pinus
kesiyaRoyle ex Gordon, Alnus maritima Mersh. ex Nutt, Pterocarpus
indicus Willd. and Swietenia macrophylla King were tested as to
survival and growth response to sewer sludge mixed media. The height and
diameter increments of Eucalyptus deglupta and Triplaris
cumingiana were significantly influenced by the sewer sludge whether pure
or in mixture with other media. Pinus kesiya Royle ex Gordon grown in
sewer sludge + topsoil + sand, performed better in height and diameter growth
than in the other media. The total dry matter yield of Triplaris
cumingiana, Eucalyptus deglupta and Swietenia macrophylla were
significantly influenced by the sewer sludge treatment.
Biomass and carbon sequestration of Gmelina arborea Roxb
One of the most
pressing problems nowadays is climate change brought about by the increasing
levels of greenhouse gases, particularly carbon dioxide (CO2), in the
atmosphere. Trees take up carbon dioxide from the atmosphere and store the
carbon in their biomass (roots, stems and foliage) through the process of
photosynthesis.
This study was
conducted to provide the basic information for accurate and reliable
estimations of the biomass and amount of carbon being sequestered in yemane (Gmelina
arborea Roxb. ) trees.
Aboveground biomass
were determined for 50 felled yemane trees aged 2-12 years covering a wide
range of diameter classes from seven provinces in Regions 3, 5, and 6. The
total green biomass of a yemane tree ranged from 2.6 to 666.4 kg. The average
tree contained 68.56% of the total dry weight in the merchantable stem, 6.45%
in the foliage and 24.98% in the topwood, branches and twigs. On the average,
6.85% of the stem (trunk) dry weight was bark abd 61.71% was wood.
Prediction equations
using allometric models were developed for estimating the fresh and oven dry
weights of the whole tree and its components using easily measured variables
such as diameter and height.
Based on the carbon
analyses done on the tree samples taken, the oven dried stemwood, bark,
branches and leaves have 46.06%, 43.53%, 44.48% and 44.89% total carbon in
their biomass, respectively. On the average, a yemane tree has 44.73% stored
carbon in its dry mass.