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1. Getting Started with Castor
Castor is a spatial, large-scale analytical model for simulating timber harvesting and it's potential influence on other forest values (e.g., wildlife habitat). It was first designed to support the government of British Columbia's caribou recovery program, by providing a tool to spatially estimate future forestry and caribou habitat conditions under hypothetical, alternative forest management regimes. It has since been and will continue to be expanded and developed to examine other forest values.
Fundamentally, the Castor model is a forest harvest simulator with the ability to flexibly "constrain" areas of the landscape to simulate alternative forest management regimes. These alternative regimes constitute specified areas (i.e., 'zones') with defined forest attribute based targets (e.g., percentage area of a certain forest age). Thus, it can be used to test how alternative forest management policies spatially applied to various zones will influence the spatial distribution and rate (i.e., annual volume cut) of timber harvest. In addition, Castor includes various modules that provide indicators of other forest values (e.g., wildlife such as caribou). Thus, the Castor model can also be used to estimate the influence of alternative forest management regimes on multiple forest values concurrently.
The Castor model is a spatial strategic model used for quantifying and accounting the impacts of forest management on various indicators over long time periods. Thus, its ability to design site specific plans and their corresponding operations is limited. Fine scale, operational decisions are important but their complexity is simplified in Castor to meet the resolution (e.g., 1 ha) and scale (e.g., multiple Timber Supply Areas, very large landscapes (> 1 M ha), long time horizons > 100 years) of landscape-scale study areas. The model uses empirical yield curves (from provincial growth models) to project the forest inventory (VRI) attributes into the future.
Human-centric decisions around harvest scheduling are the main assumptions in the model, and include WHAT, WHERE, WHEN and HOW much timber to harvest. The model is given a demand of timber volume for each time period (i.e., the HOW much) and the goal of Castor is to “find” that timber volume while meeting various objectives often described as constraints such as no harvest areas and various land-cover constraints. Castor uses some rules around minimum harvest criteria (i.e, merchantable volume per hectare > 150 m3 per ha, etc) to determine WHAT gets harvested. Castor simulates the harvesting schedule with a priority (some pre-determined schedule known a priori, closest to disturbance, oldest age, etc) to figure out the WHERE and WHEN to “find” the timber volume in a specific time period. The timber harvesting that's simulated in Castor can be “greedy” in that it can’t figure out how to find the optimal harvest schedule. The result of a Castor simulation is a PLAUSIBLE harvesting sequence that allows cutblock size, adjacency and other spatial considerations.
The purpose of Castor is compare alternative plausible scenarios of various human-centric forestry decisions in a simulation environment. The relative comparison between scenarios is the true benefit of these analyses, whereas, the absolute values of the outcomes should be used with caution. What is deemed plausible is left to the quality of the information being used and the resulting logic of the human-centric decisions about harvest scheduling.
The code in this GitHub repo is open-source and provides a transparent record of the Castor model. Anyone can download, reproduce and apply the model. However, this is not a self-contained piece of software. In particular, using Castor as-is requires a data management framework, or modifying the code here to work with your preferred data management framework. The repository here also consists of code to create frontend apps to develop Castor model scenarios and review outputs.
You can use our Wiki to help you with understanding the structure and functions of the Castor model. We also have a tutorial that will describe the steps to get a basic Castor model up and running.
Once you are familiar with Castor, if you find any errors with the code, please submit them via the GitHub "Issues" tab.
For more information on working with the Castor team and model to support a forest management problem, please don't hesitate to contact Tyler Muhly ([email protected]), Team Lead, Strategic Analysis, Forest Analysis and Inventory Branch, Office of the Chief Forester, Ministry of Forests.
Tyler Muhly, Team Lead, Strategic Analysis, Forest Analysis and Inventory Branch, Office of the Chief Forester, Ministry of Forests
Kyle Lochhead, Ecological Modeling Specialist, Forest Analysis and Inventory Branch, Office of the Chief Forester, Ministry of Forests
Elizabeth Kleynhans, Ecological Modeling Specialist, Forest Analysis and Inventory Branch, Office of the Chief Forester, Ministry of Forests
Mike Fowler, Spatial Data Analyst, Forest Analysis and Inventory Branch, Office of the Chief Forester, Ministry of Forests
Cora Skaien, Ecological Modeling Specialist, Forest Analysis and Inventory Branch, Office of the Chief Forester, Ministry of Forests
Copyright 2022-2024 Province of British Columbia
Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
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