❓ Hon Diane Evers asks about the methodology and timeframe for estimating marri tree growth rates in WA. The response outlines various methods used by DBCA, including direct measurement, dendrochronology, and forest inventory systems.
AnsweredQoN 1901Legislative Council
QuestionView source ↗
(1) How is the growth rate of marri estimated (please list all relevant documents used to make the estimate).? (2) Over what dates has the estimate been made?
AnswerView source ↗
Answered
10 April 2019
Responded by
Minister for Environment
Response time
10 days
(1) and (2) In south-west forests marri generally occurs mixed with mostly jarrah and/or karri. Growth rates for each tree species vary greatly with tree age, climate, site conditions and relative density (or structure) of the stand. The pattern of growth over time also varies depending on the variable measured (such as diameter, height or volume).
Growth rates for marri can be estimated directly from measurement of trees of known age over extended periods of time, or indirectly using dendrochronological techniques such as tree ring counts. Both approaches have been used at various times and for specific purposes by the Department of Biodiversity, Conservation and Attractions (DBCA) and predecessor agencies. In forests available for timber production, DBCA maintains a strategic forest inventory system which includes plots containing marri from which growth can be estimated, as well as various silvicultural research experiment plots. A series of Sustained Yield information sheets is available on the DBCA website that explains the process and basis of calculations of growth and yield used in preparing the Draft Forest Management Plan 2014-2023.
Growth rates for marri can be estimated directly from measurement of trees of known age over extended periods of time, or indirectly using dendrochronological techniques such as tree ring counts. Both approaches have been used at various times and for specific purposes by the Department of Biodiversity, Conservation and Attractions (DBCA) and predecessor agencies. In forests available for timber production, DBCA maintains a strategic forest inventory system which includes plots containing marri from which growth can be estimated, as well as various silvicultural research experiment plots. A series of Sustained Yield information sheets is available on the DBCA website that explains the process and basis of calculations of growth and yield used in preparing the Draft Forest Management Plan 2014-2023.
Explore WA Government Data
Search the full archive in the free dashboard, or query programmatically via API.
Explore more
Government Gazette
Appointments, regulatory notices, planning changes.
Hansard
Debates, questions, speeches and sentiment.
Tabled Papers
Reports and documents tabled in Parliament.
Committees
Committee profiles and recent reports.
Regulations
Subsidiary legislation with filters and summaries.
Bills
Proposed laws and parliamentary progress.
Acts
Current WA legislation and summaries.
Explanatory Memoranda
Bills with EMs (text/PDF) available.
Members
MP profiles, party breakdown and rankings.
Pollie Rankings
Data-driven rankings across 19 categories.
Amendment Chains
Track how schemes and regulations evolve over time.