Restoration and management of callitris forest ecosystems in Eastern Australia: Simulation of attributes of growth dynamics, growth increment and biomass accumulation

Availability of quantitative information on growth increment, biomass accumulation and growth dynamics of fragmented and degraded forest ecosystems is a common challenge in restoration work. Ecological models of forest dynamics have the potential to provide a structure through which data, observations and assumptions can be combined and explored. The utility of such models, however, is often limited by lack of validation. In this paper we used growth data for 143,200 tree measurements, in 121 plots spanning up to 70 years of forest monitoring from uneven-aged mixed species callitris forests of Australia to test the Ecosystem Dynamics Simulator (EDS). These are among the least known and most degraded forest communities in Australia and are known habitat for threatened and rare fauna species including brush-tailed rock wallaby (Petrogale penicillata), glossy black-cockatoo (Calyptorhynchus lathami), grey falcon (Falco hypoleucos), golden-tailed gecko (Strophurus taenicauda) and others. We determined growth parameters for 26 woody species and applied these to the EDS to validate projected stand structure and growth. The model projections explained 93.9% (diameter at breast height (dbh)), 88.9% (basal area), 90.5% (stem density) and 88.6% (aboveground biomass) of the observed variation. To our knowledge, this is one of the most accurate validations of forest dynamics simulation achieved to date. Diameter growth rates for most species were <0.3 cm yr−1 and reproduced well by the EDS, for all the species in the callitris forest communities. These growth rates indicate that exceptionally long periods will be required to restore the degraded or cleared forests to a mature state. Results can guide restoration and sustainable management of callitris forest ecosystems by providing projected measurable forest attributes to meet multiple goals, including harvesting of forest resources, carbon storage and conservation of biodiversity.