A Markov Chain Model for Simulating Wood Supply from Any-Aged Forest Management Based on National Forest Inventory (NFI) Data

Abstract

Markov chain models have been applied for a long time to simulate forest dynamics based on transitions in matrices of tree diameter classes or areas of forest size and structure types. To date, area-based matrix models have been applied assuming either even-aged or uneven-aged forest management. However, both management systems may be applied simultaneously due to land-use constraints or the rationality of combining the systems, which is called any-aged management. We integrated two different Markov chain models, one for even-aged and another for uneven-aged forest management, in an area-based approach to analyze wood supply from any-aged forest management. We evaluate the impacts of parameterizing the model based on available data sets, namely permanent and temporary Finnish National Forest Inventory (NFI) sample plots and a plot-level simulator to determine transitions due to different types of thinning treatments, and present recommendations for the related methodological choices. Our overall observation is that the combined modelling chain simulated the development of both the even-and uneven-aged forest structures realistically. Due to the flexibility of the implementation, the approach is very well suited for situations where scenario assumptions need to be varied according to expected changes in silvicultural practices or land-use constraints, for example.

Shifting from even-aged management to less intensive forestry in varying proportions of forest land in Finland: impacts on carbon storage, harvest removals, and harvesting costs

“…We simulated the future development of forests in Finland using an area-based Markov chain model (cf. Vauhkonen and Packalen 2017). Our analyses considered almost the entire forest land of Finland, excluding northernmost areas and forests located in the southern archipelago, which are considered to have a low importance in terms of wood supply of Finland.…”

“…As in Vauhkonen and Packalen (2017), the forests were assigned to wood availability categories according to forest use restrictions in the NFI data: initially, 10.1% and 10.6% of the total forest area were classified as FNAWS and FRAWS, respectively, with the remainder classified as FAWS. In order to study the national-scale effects of diverging from the current management system, varying proportions of forest were removed from FAWS and assigned to either FRAWS or FNAWS.…”

“…the last year in the simulation period is approximately 2060, depending on the initial measurement year). The initial forest state, (business-as-usual) transition and activity probabilities, and output coefficients for the model were derived from the NFI11 data according to the workflow presented by Vauhkonen and Packalen (2017) based on using permanent NFI plots as pairwise data for natural processes. Appendix 2 also illustrates the process of deriving the initial state and the simulation of the future development of one example forest.…”

“…From the point of view of provisioning of non-wood forest products or other ecosystem services, it is useful to also simulate the development of area and growing stock in the remaining areas-i.e. in Forests Not Available for Wood Supply (FNAWS) and Forests with Restrictions on Availability for Wood Supply (FRAWS; see also Vauhkonen and Packalen 2017). Extensive forest inventories, such as the National Forest Inventory (NFI), also provide data for the simulation of transitions due to growth or management for forests prioritized for uses other than solely wood production.…”

“…Vauhkonen and Packalen 2017) could be more suitable for area-based projections of forest dynamics based on the NFI data. Vauhkonen and Packalen (2017) simulated the development of forest size and structure classes derived from NFI data by combining multiple Markov chain models for different silvicultural systems. In their study, classification of forests to wood availability categories determined which system was applied.…”