Coffs Harbour City Council, in association with the Office of Environment and Heritage, has undertaken this project to survey and map patches of old trees and significant arboreal habitat. The aim of the High Value Arboreal Habitat study was to produce a map of the forests which contain large, old and hollow bearing trees in the Coffs Harbour Local Government Area (LGA).
At its Ordinary council meeting of 8 May 2014 the following digital layers and report were adopted as corporate layers:
The Document and Maps
The High Value Arboreal Habitats in the Coffs Harbour Local Government Area May 2014 Final Report.
Coffs Harbour City Council's Online Mapping Tool is where you can access the High Value Arboreal Habitat Layers.
How to access the High Value Arboreal Habitat Layers.
The High Value Arboreal Habitat Project Background
The eucalypt forests of the North Coast of New South Wales have been recognised as some of the most diverse and species-rich communities in the world. These forests include high levels of both eucalypt species found nowhere else and the highest diversity of different eucalypts found anywhere.
In the Coffs Harbour LGA, eucalypt and rainforest plant communities dominate the landscape covering over 60% (54,750 hectares) of the LGA. This is mainly due to the rich, fertile landscapes and high annual rainfall.
Of the 26 known species of eucalypt in the Coffs Harbour LGA, Blackbutt is the only species for which information has been collected on hollow formation. These studies show that the size and number of hollows increases with the size and age of the tree. They also show that there are apparent differences between species.
In dry sclerophyll forests in the Coffs Harbour area, it is likely that hollows begin to form in trees >50 cm DBH, and in
wet sclerophyll forests hollows begin to form in trees >80 cm DBH (McLean 2012).
It is the older trees that provide hollows suitable for a range of fauna, and it is the older trees that provide the greatest number of hollows. Fire frequency also plays a significant role in the development of hollows within eucalypts. Hollows are scarce in trees under 80 years of age and it may take as long as 150 to 220 years for trees to develop a diversity of larger hollows.
Forests supporting old trees are recognised as having very high aesthetic, cultural and natural conservation values. Their protection and management is extremely important in maintaining biodiversity.
The purpose of the project was two-fold:
- use aerial photo interpretation to produce a fine-scale maps, this was conducted over 49,894 hectares of forested freehold lands in the Coffs Harbour LGA.
- produce a classification system for HV arboreal habitats in the Coffs Harbour LGA.
The project was carried out in five stages:
- Define HV arboreal habitats in Coffs Harbour LGA.
- Use Aerial Photography Interpretation to map areas of HV arboreal habitat.
- Cross-check mapping against CRAFTI candidate old-growth forest mapping.
- Undertake field surveys to validate areas mapped as HV arboreal habitat.
- Refine mapped boundaries of HV arboreal habitats and finalise.
HV arboreal habitats were classified into four categories
- HV arboreal habitat category 1 — old-growth forest
- HV arboreal habitat category 2 — forest areas >10 hectares with ≥ 5 senescent trees per hectare
- HV arboreal habitat category 3 — forest areas 5–10 hectares with ≥ 5 senescent trees per hectare
- HV arboreal habitat category 4 — forest areas 1–5 hectares with ≥ 5 senescent trees per hectare.
Field validation was undertaken at 149 survey sites to support the classification and mapping program.
The final mapping shows 1502 hectares of HV arboreal habitats on freehold lands in the LGA. This represents less than 3% of freehold forested lands.
The development of the HV arboreal habitats map has been an initiative supported by Coffs Harbour City Council and the Office of Environment and Heritage (OEH). This project is part of the Biodiversity Action Strategy Implementation.