Our first issue presents papers on science writing, subcanopy forest analysis, modeling and optimisation. Mike Mentis (2014) opens the issue with Science Writing in the Real World. This entertaining and thought provoking contribution questions common assumptions (“a hallmark of written science and technology is that every statement is capable of being tested and capable of being shown to be wrong, and that methods yield repeatable results”) and warns that it is not only the content of messages that matters, but reliability too. I like his statements on parsimony. No description, experiment, explanation, … model, … should be more elaborate than necessary to satisfy its purpose, which reminds me of Oscar García who once said something like “increasing complexity requires simpler models”. Mike is a former professor at the University of the Witwatersrand in South Africa who now works as an environmental consultant and practical ecologist in different regions of the world.
This is succeeded by Timo Pukkala’s (2014) contribution which is entitled “Stand management optimization – the role of simplifications”. Simulation studies are often based on simplified assumptions (neglecting natural regeneration; simplified harvest events) and this study analyses the impacts of simplifications by gradually reducing the number of simplifying assumptions. The results showed that forced low thinning, cleaning the plantation from the natural regeneration of mixed species, and ignoring advance regeneration all have a major impact on optimization results. Timo is widely recognized for his pathbreaking studies on ecosystem dynamics and landscape optimisation and his contribution will generate much interest among forest design specialists.
Supportive to Timo’s contribution are two additional studies from Finland. Olavi Laiho et al. (2014) present “Height increment of understorey Norway spruces under different tree canopies” and Sauli Valkonen et al. (2014) “Ingrowth, survival and height growth of small trees in uneven-aged Picea abies stands in southern Finland”. There is renewed interest to test the potential of continuous cover forestry (CCF) in Scandinavian countries, and studies on growth survival of small trees are essential.
Corral-Rivas et al. (2014) are using mixed models with random components to develop height-diameter functions for mixed, uneven-aged forests in the State of Durango in Mexico. Sacramento and his co-authors from Mexicoand Spain are using measurements from 44 permanent plots in the North of Durango. The results of their work, involving several species of Pinus, Quercus, Cupressus, Arbutus and Alnus are useful for estimating forest biomass in a rather unknown but (because of the unique social-ecological settings) most interesting forest regions of the world.
Last but by no means least is Jerome Vanclay’s (2014) highly interesting paper “Unsuspected implications arising from assumptions in simulations: Insights from recasting a forest growth model in system dynamics”. Jerome Vanclay is well known for his fundamental studies on multi-species forest ecosystems. He warns that “familiarity with a simulation platform can seduce modellers into accepting untested assumptions for convenience of implementation” and “modellers should remain conscious of all assumptions, consider alternative implementations that reveal assumptions more clearly, and conduct sensitivity tests to inform decisions”. This paper is another very important contribution, especially relevant to users of forest dynamics software that is based on individual tree models.
We trust that you will enjoy this first issue of Forest Ecosystems with a set of papers that do not only inform, but stimulate and challenge. We look forward to the active participation of many readers and contributors who will support us in creating a truly international forum for presenting research and debating significant issues which will lead to improved understanding of the structure and dynamics of natural and domesticated forest ecosystems.
Yin Weilun and Klaus v. Gadow