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THE POPULATION STRUCTURE OF SELECTED TREE SPECIES WITHIN THE FOREST RESERVES AND THE IMPACTS OF LOGGING ON FOREST STRUCTURE
AIM
To assess the impact of logging on forest structure and tree species distribution within the two study grids of Kakenauwe and Lapago.
OBJECTIVES
INTRODUCTION
The
impact of logging on forest structure will be compared in two grids which are
known to suffer from different levels of logging and disturbance. The Kakenauwe
grid is positioned by the road and is known to suffer from edge effects and
selective logging. By contrast the Lapago grid is located towards the center of
the larger Lambusango reserve and is a more pristine rainforest. By constructing
a population structure of targeted tree species within the study grids it will
enable a picture of the varying spatial pattern of tree species distribution and
their age class structure to be constructed. This map will be used in
conjunction with the various Silvi Star transects completed to provide an
overall picture of the impact of logging on forest structure and tree species
distribution. There is known to be active forest clearance in some parts of
Buton Island with utilization of forest products and selective logging. There is
increasing concern that the rate of forest clearance is accelerating and so it
is of paramount importance that conservation measures are set up to upgrade the
two existing nature reserves to National Park status. This project will
hopefully provide insight into the varying impact of disturbance on forest
structure and tree species distribution, so that effective conservation measures
can be implemented.
METHODS
The
study was conducted during the months of July and August 2002 and consisted of
two main methods. A population structure of the tree species distribution was
conducted in the study grids of Kakenauwe and Lapago, where all trees along
various different transects were identified to species level and their x and y
grid coordinates were recorded for later mapping. Tree circumference for each
tree was measured as well as the particular use of the tree. Once this data has
been entered into an excel spreadsheet various comparisons can be displayed
graphically such as the varying spatial pattern of tree species distribution and
their age class structure – which can be related to varying levels of human
disturbance.
Another
method used for assessing the impact of logging on forest structure was through
the use of Silvi-star transects whereby various indexes for assessing the level
of disturbance were looked at. For example the height of mosses, the presence of
rattan and the percentage of sky cover were some of the many categories used for
assessing overall forest structure along various transects running away from the
paths.
INITIAL
RESULTS
Much data is still to be collected, however initial findings suggest that the level of disturbance is indeed significantly greater in the Kakenauwe grid than the Lapago grid, although other variables such as altitude and geology need to be taken into account when attributing changes in forest structure and tree species composition to human disturbance alone. This project should throw further light on the effect of selective logging on the forest structure and population structure of selected tree species.
REPORT
A report entitled The population structure of selected tree species in the Lambusango and Kakenauwe forest reserves and the impact selective logging will have on the forest structure will be produced by Alex Woodcraft of Exeter University by May 2003.