Masashi Konoshima

Stand-Level Forest Management Planning Approaches

Seeking an optimal operational regime under different management environments has been one of the main concerns of forest managers. Traditionally, the main operational regime includes planting density or regeneration scheme, thinning time/intensity, and optimal time to harvest over the given time horizon. Deterministic approaches to tackle this type of optimization problem with different controls have dominated the solution techniques in forestry literature. We present in this paper an overview of the methodologies used in stand-level optimization, in which we show the strengths and weaknesses of these methodologies as well as provide comments on the effectiveness of the methodology. We then propose a new dynamic programing approach for generalizing solution specification and techniques.

Spatially constrained harvest scheduling for multiple harvests by exact formulation with common matrix algebra

Exact formulations currently developed for spatially constrained harvest scheduling problems mostly consider only a single harvest over time for individual forest units. We propose a new method for formulating the scheduling problem of allowing multiple harvests over time by using common matrix algebra. We combine the concept of Model I formulation, which defines treatments to overcome issues of multiple harvests, with that of adjacency constraints for treatments. Conflicting harvests over space and time are resolved by introducing two kinds of adjacency matrices. One is an ordinary spatial adjacency matrix for the forest unit location, and the other is a newly introduced activity adjacency matrix to identify concurrent harvesting activities in a set of possible treatments for one forest unit. The Kronecker product of these two adjacency matrices is used to generate the entire adjacency constraint for treatments among all forest units to avoid adjacent harvests. The advantage of our approach is that it relies on the concept of the Model I formulation to satisfy spatial restrictions and identify decision variables for treatments of all forest units systematically using common matrix algebra, so that conversion and extension of existing non-spatial forest planning models (e.g., FORPLAN) to consider multiple harvests and green-up constraints can easily be achieved in a spatially explicit manner.

Constructing tree stem form from digitized surface measurements by a programming approach within discrete mathematics

Key messageThe main message of this work is the demonstration of possibility of creation of stem shape from digitized points using integer-programming approach. The points are digitized by magnetic motion tracker which in contrast to the laser scanning allows the reconstruction of complete cross-section of stem even in the “hidden (invisible)” part.AbstractThree-dimensional information on tree stem form plays an important role in understanding the structure and strength of a standing tree against the forces of wind, snow, and other natural pressure. It also contributes to precision in volume measurement compared to conventional two-dimensional measurement. We investigate approaches for obtaining three-dimensional information of tree stem form from partially organized surface measurements, acquired using a three-dimensional digitizing device (Polhemus FASTRAK® motion tracking device). We then propose a new programming approach from discrete mathematics to construct tree stem form. Our method is based on an optimal connection of neighbor triangles for surface construction, which is created by locally possible combination of three digitized points on the stem surface. We compare the proposed method to the existing heuristic methods of contour tracing and region growing. Our analysis shows that the proposed method provides a consistent construction of tree stem form, for even stems with extremely irregular structure such as those from bent trees and mangrove trees with unique root spread, while the other methods are incapable for constructing such tree stems.

How well are biodiversity drivers reflected in protected areas? A representativeness assessment of the geohistorical gradients that shaped endemic flora in Japan

Protected areas function as a lifeboat that can preserve the origins and maintenance of biodiversity. We assessed the representativeness of biodiversity in existing protected areas in Japan using a distribution dataset and phylogenetic tree for 5565 Japanese vascular plant species. We first examined the overlap of species distribution with the existing protected areas and identified the minimum set representing all plant species. Second, we evaluated the relative importance of environmental variables in explaining the spatial arrangement of protected areas using a random forest model. Finally, we clarified how potential drivers of plant diversity were sufficiently captured within the protected areas network. Although the protected areas captured the majority of species, nearly half of the minimum set areas were selected from outside the existing protected areas. The locations of existing protected areas are mainly associated with geographical and socio-economic factors rather than key biodiversity features (including evolutionary distinctiveness). Moreover, critical biodiversity drivers, which include current climate, paleoclimatic stability, and geographical isolation, were biasedly emulated within the existing protected areas. These findings demonstrate that current conservation planning fails to represent the ecological and evolutionary processes relevant to species sorting, dispersal limitation, and allopatric speciation. In particular, under-representativeness of historically stable habitats that function as evolutionary hotspots or refugia in response to climate changes may pose a threat to the long-term persistence of Japan’s endemic biota. This study provides a fundamental basis for developing prioritization measures to retain species assembly processes and in situ diversification along current climatic and geohistorical gradients.

Combining market and traditional values in tribal forestry using interactive forest decision synthesis (INFODS)

Forestry joint production choices require clear relative values for multiple, and often conflicting, management objectives. Optimization is most difficult where values of forest attributes are: intangible, non-market, or sensitive. When most mathematical programming models are adapted for non-commensurable objectives, there is little guarantee that vague relative preference sets are met. We demonstrate how an iterative multiple objective programming approach finds preferred joint solutions in a Native American tribal forestry case where marketable outputs are managed in the context of traditional culturally based forest values. Without a priori specification of traditional tribal cultural values, conducting a series of feedback processes does appear to identify more preferable solutions than other types of multiple-objective models that do not use feedback.