Date of Award

2003

Degree Type

Thesis

Degree Name

Bachelor of Science Honours

Faculty

Faculty of Computing, Health and Science

First Advisor

Dr Eddie van Etten

Abstract

Forests are decreasing globally and there are pressing requirements for ecologically sustainable forest management to be implemented at all scales. There has been some criticism of the public managers for forests and the processes used to select reserve systems and silvicultural methods used. Limited research has been conducted on the effects of logging on the plants of the northern Jarrah forest of south western Australia, While fire is a major disturbance event, disturbance during logging operations may remove non-commercial trees, understorey shrubs and change soil conditions. Some plants that regenerate from below ground storage organs such as Cryptophytes (Geophytes) may be affected by logging disturbance. Old growth forest by definition can be considered to be free of many of the disturbances found in logged forest, and offered a useful control for determining logging effects particular plant groups. Research was carried out to determine under semi-controlled conditions, whether plants such as cryptophytes differed between logged and oldgrowth areas in the northern Jarrah forest. Field research was conducted at three separate areas in the northern Jarrah forest using paired one hectare sites of logged and oldgrowth forest each containing four replicate quadrats. Paired sites were selected that had minimal differences between variables of soil, landscape position, spatial separation and time since last fire. Temporal sampling was conducted for all vascular plants including Cryptophytes in particular. Site characteristics of stand structure and composition were also measured, along leaf litter depth and soil sampling. Soil samples were tested for a range of physico-chemical properties. The results indicated that cryptophyte composition can differ between logged and oldgrowth areas. The logged areas tended to have fewer cryptophyte species and lower abundance. The mean number of trees, slope, the mean diameter of Jarrah trees and leaf litter were correlated with cryptophytes at some sites. The conclusions were that logging disturbance at the studied areas of the Jarrah forest was very likely to be the factor for reduced cryptophyte abundance and that future management needs should consider a review of practices to limit impacts.

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