Professor Jerry Vanclay

The selected case studies illustrate a series of key factors that make a publication impactful in the sense of providing deep insight or durable utility. Some of these factors include: establishing key information to help clients perform better, enabling multiple ways to fact-check forecasts, providing good documentation that is easy to understand, ensuring all stakeholders are involved, focusing on potential solutions rather than the apparent problem, being open to alternative interpretations and prepared to change research direction as needed, finding practical analogues when the ideal task is too challenging, ensuring redundancy in case something goes wrong, and carefully reviewing all aspects of one’s work to find possible improvements.

This study aimed to develop and validate a growth and yield simulator using a distance independent tree model for the forests of Jari Florestal S.A. forests, incorporating the productive capacity of the site as a prediction attribute. The data came from an experimental area belonging to Jari Florestal S.A., under monitoring since 1983 of Embrapa Amazônia Oriental, with 8 distributed measurements in 32 years of monitoring plots. The experiment has 12 treatments plus a control treatment, distributed in 40 plots, 13 of those intended to validate the proposed model. All trees with DBH ≥ 5 cm were used to compose the mixed effect models describing the diametric growth, mortality and recruitment. The species were separated into ecological, economic and growth rate groups, accounting for 13 species groups and 32 subgroups by combining all 3 categories. Were tested 9 variables as site productivity indicative of composing the simulation submodels. The simulator was implemented in Simile visual modeling software, and its scenarios were submitted to 5 statistical tests to validate the results. The proposed simulator presents reasonable results and good accuracy, providing significant results in the simulation of all management regimes in the experiment.

Forest environments have been found to benefit mental health and wellbeing, however there is little research on which forest features are more effective. Here, original research articles are reviewed to examine the impact of particular forest features on mental health and wellbeing. A systematic scoping review following the Joanna Briggs Institute methodological guidelines reviewed 33 articles. Findings from this review indicated that all types of forest had beneficial outcomes on mental health and wellbeing. These findings suggest that all forests have the potential to induce positive and reduce negative effect. The review also revealed the need for greater understanding of impact of forest type on mental health and wellbeing. It is recommended that all future research include detailed reporting of the forest environment to understand the features most effective for mental health and wellbeing.

Claims that the catastrophic flooding events of 2022 which devastated the Northern Rivers region of New South Wales were unprecedented are demonstrated here to be ill-informed. Additionally, flood mitigation efforts will not be able to protect Lismore and surrounding communities from the ravages of future floods. It is essential that geographical realities be at the heart of planning decisions to protect flood prone communities in future. The inescapable fact is that catastrophic floods will recur in the region. The lesson for this region, and for others throughout Australia which are subject to severe flooding, is that planned withdrawal of critical services, commercial premises and vulnerable housing from the flood plain is the only sure way to protect people, their homes and livelihoods from repeated devastation. Geography matters indeed.

A ground-based survey of 400 Eucalyptus tereticornis trees examined the incidence of visible hollows suitable for hollow-dependent fauna. As well as the expected relationship with stem diameter, data analysis revealed a relationship between the incidence of hollows (with entrance diameter ≥10 cm) and spacing between neighbouring trees. When the distance between trees is equivalent to 0.3 times total tree height, a tree is more likely to suffer branch breakage and subsequent hollow formation. This influence of spacing, likely due to branches clashing during storms, appears to contribute a twofold difference in the incidence of hollows. This offers opportunities for the management of regrowth forests and restoration plantings, especially where one of the objectives is to encourage the formation of hollows.

Mixed-species systems are well-suited to smallholder and community forestry, but reliable evidence regarding and procedures to assess species performance in such systems is scarce. This field trial uses a pair of clinal plots with varying spacing and species composition to gain insights into competition between four species proposed for landscape rehabilitation in the Philippines. We examine the efficiency of this compact clinal trial in revealing growth traits of four species (Paraserianthes falcataria, Pterocarpus indicus, Shorea palosapis, Swietenia macrophylla) in mixed plantings. The use of a size-distance competition index allowed an assessment of the competitive and collaborative influences between four tree species. Within the expected general trend for diameter increment to decline with increasing competition, there were indications that Shorea palosapis is a benign competitor that may stimulate the growth of neighbouring individuals. Paraserianthes falcataria is a strong competitor that is also strongly impacted by competition, especially through antagonistic intraspecific competition. Paraserianthes falcataria appears well suited as a solitary tree in a field or village, whereas Shorea palosapis seems ideal for plantations, in both monoculture and mixed plantings. The clinal spacing and mixture trial, when examined using a size-distance competition index based on diameter increment, revealed useful insights into species performance. Pterocarpus indicus exhibits strong intraspecific, but low inter-specific competition, so appears well-suited for polyculture plantings. Of the four species trialled, Swietenia macrophylla appears to be best-suited as a monoculture species as it exhibits the lowest intraspecific competition.

Reliable estimates of forest productivity at the site scale can guide site-specific forest management. However, the best methods to evaluate productivity of natural forest sites, and in particular secondary natural forests, remain undefined. In this study we: (1) applied an indirect method for estimation of the potential productivity of a forest site (‘site form’) in Dong Nai Biosphere Reserve. In addition, we: (2a) investigated the influence of a range of environmental conditions on site form, (2b) built models to estimate site form from the corresponding environmental variables and (3) generated site form maps for the region. We found that Michaelis–Menten models provided the most consistent representation of tree height–diameter relationships, with reliable anamorphic curves at both plot-scale (50 m × 20 m) and multiplot-scales. Predicted tree height at 25-cm diameter (H25) was selected as the best indicator for site form as 25 cm was both a tree size, which was common in the forests, and for which height could be accurately predicted. H25 was significantly correlated with site environmental conditions, with the dominant influences being factors related to water availability. We generated site form maps for Dong Nai province based on the relationship between known environmental variables and H25. We conclude that maps such as these could have broad application in guiding tropical forest restoration measures elsewhere, particularly where there is limited knowledge of tree ages and species.

Allometries that include height as independent variable usually provide greater accuracy on estimates of volume, biomass or individual carbon than other prediction strategies that rely only diameter at breast height as independent variable. However, when these models are applied in Amazon Forest Inventories, it is common to use estimated heights rather than measured heights to prepare volume, biomass or carbon estimates. This practice is common, but rarely discussed and the effect on predictions and precision is usually overlooked. The aim of this study was to examine hypsometric models and evaluate the effect of estimated height on merchantable volume prediction in Eastern Amazonian forests. The study area was a 3,786 ha Forest Management Unit owned by Jari Florestal S.A., in the Jari Valley Region of the State of Pará, Brazil. The data includes 16,099 trees of 25 species, measured and harvested in 2006. Ten percent of the data were reserved for validation of the hypsometric and volumetric estimates. Five hypsometric models and two modelling techniques (linear regression and mixed-effects model) were examined. The choice of best model was based on graphical analyses of residuals, distribution of residuals, heteroscedasticity of error and presence of outliers as assessed by h-values, DFFITS and Cook's distance. The hypsometric relationship and volumetric estimates using DBH and DBH with estimated height were validated with Graybill's test, Theil's error decomposition, Efficiency, Equivalence test and Tukey's test for species estimates level. Heights estimated using a semi-logarithmic mixed-effects model can improve predictions from volume equations. The results show that exploratory data analysis and validation process helped to provide estimates with greater efficiency and should be adopted in related studies. The prediction of height associated with volumetric models for six different species provided volumetric estimates with an error below 5% for the global average volume. The estimated height by the mixed-effect non-power law model should be included in double input models previously developed for volume prediction.

•Medium- and high-intensity thinning facilitated recruitment of Flindersia trees.
•Medium intensity thinning promoted Flindersia individual tree growth rates most.
•Flindersia tree growth rate was influenced by tree size, crown size and class most.
•Only Flindersia tree growth rate in high intensity thinning changed over 46 years.

Studies in low-diversity temperate forests clearly establish that thinning leads to increased growth of remaining trees. However, few studies have investigated the long-term impacts of thinning regimes on the growth responses of tropical timber species. In this study, we analysed data collected over a period of 46 years to assess the long-term growth responses and growth patterns of remnant trees of three key commercial species (Flindersia brayleyana F. Muell., Flindersia bourjotiana F. Muell. and Flindersia pimenteliana F. Muell.). We also examined how initial tree size, crown size and crown position within canopy, and neighbourhood competition affected growth rates of the three Flindersia species. Within these species, we assessed growth responses of trees above 10 cm diameter at breast height (DBH) in an Australian tropical rainforest, to different intensities of thinning i.e. logging only as a control and low-, medium- and high-intensity thinning (L, LT, MT and HT, respectively). Medium and high intensity treatments facilitated recruitment of all three Flindersia species into the >10 cm DBH class while medium intensity thinning resulted in the greatest average annual basal area increments (BAIs). The lower individual BAI of Flindersia species in HT was due to fewer large Flindersia trees remaining after thinning, combined with large numbers of recruits and slow growth of small remnant trees. BAI in HT increased initially, with a peak during 1981–1989 and then decreased. BAI was constant and varied little over time within the other treatments. High intensity thinning had prolonged impacts on the growth patterns of Flindersia trees over 46 years. Tree initial DBH, crown size and crown position within canopy explained most variation in individual BAIs of Flindersia trees. Both thinning intensity and measurement periods explained variation in individual BAIs of Flindersia trees. Larger remnant Flindersia trees with broad and dominant crowns tended to grow faster. BAIs of individual trees were negatively correlated with neighbourhood competition. If the goal of tropical native forest management is to improve productivity of target species, the results indicate that thinning should be sufficiently intense to reduce neighbourhood competition while maintaining large diameter commercially desirable trees with large and dominant crowns, which may consequently facilitate the timber volume and above-ground biomass recovery after selective logging.