|Question On Notice No. 1904 asked in the Legislative Council on 12 March 2019 by Hon Diane Evers |
Question Directed to the: Minister for Environment
Minister responding: Hon S.N. Dawson
Parliament: 40 Session: 1
Will the Minister please provide the litter accumulation rates for Jarrah, Karri and Wandoo for:
(a) 50 years;
(b) 100 years; and
(c) if no, why not?
Answered on 10 April 2019
This specific information is not available, however it could be estimated using Forest Fire Behaviour Tables (Sneeuwjagt and Peet 1985). These tables provide guidance regarding the litter accumulation in jarrah and karri dominant stands based on the number of annual leaf falls and the canopy cover of the forest. The tables provide for up to 25 annual leaf falls with accumulated litter after 25 years ranging from 14.8 tonnes per hectare (t/ha) to 22.5 t/ha in jarrah dominant forest and from 35 t/ha to 58 t/ha in karri dominant forest. For wandoo dominant forests, the tables indicate litter accumulation for up to 30 annual leaf falls based on either the basal area or canopy cover of the stand, with accumulated litter loads after 30 years ranging from 5.4 t/ha to 15.8 t/ha.
The process of litter accumulation is influenced by a range of factors including:
- the age, canopy cover and structure of the forest overstorey;
- the density, condition and species composition of mid-storey trees and understorey shrubs;
- events that affect the condition of the forest canopy including drought, frost and insect defoliation; and
- decomposition rate of litter which is affected by moisture, temperature and biotic activity.