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NOTES AND QUERIES
may have carried tea bushes, though plucking would not have been easy.
d) Note that small trees and shrubs in and around the stream-bed were not seriously damaged by the fire of late 1975. The survival of trees beside water-courses, when the surrounding vegetation is burnt, is one of the bases for the existence of riverine forest or gallery forest in parts of the wet tropics that are influenced by man.
4. The Return Journey
On the Society's excursion, the party retraced its route to Tsuen Wan. However, it is more interesting to return to Route Twisk, and then proceed northward to Shek Kong. Two other points of interest between the Stop B and Shek Kong will be described below, both of them relating to management of the countryside.
Countryside Management I
About 400 metres up Tai Mo Shan Road from Stop A, on the up-hill side of the road, is a site where some effects of fire have been studied.
About 1970 the hillside was planted with Acacia confusa so that there was a rough grassland with some shrubs (grassland in transition to scrubland), and with small trees of A. confusa spaced regularly within it. By January, 1976 the Acacia had grown to a height of about 1.5 metres and their crowns covered perhaps 50% of the ground below. In that month a hill fire burnt part of the area so that there was a clear boundary between the burnt and unburnt portions. Obviously, this provided an opportunity to study both the effect of fire on the vegetation and the influence of establishing trees in a grassland.
The effect of an increasing cover of trees will be considered first by reference to changes taking place at the unburnt site. By October -- November 1976 the canopies covered 56% of the ground beneath and a year later this had increased to about 67% so that, on a sunny day, the amount of sunlight reaching the ground beneath the canopy was about 15% of that reaching the ground surface outside the canopy. Partly as a result of the reduced sunlight, the dry weight of plants beneath the acacias (grasses, herbs etc.) was
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