1. Background and Research Question:
The goal of my work in this course is to assess the influence of forest governance on spatial patterns of forest disturbance. Forest governance can be understood as forest-related decisions, their implementation and resulting effects within a given institutional setting, whereas forest disturbances are events that cause change in the structure and composition of a forest ecosystem. For this course, I’ll be focusing my analysis on disturbances associated with timber production, e.g., clear-cutting and partial harvests. My study area is Willamette National Forest, which encompasses roughly 6,800 square km in the central portion of Oregon’s West Cascades.
Governance of the Willamette and other federally managed forests of the Pacific Northwest is shaped largely by the Northwest Forest Plan (NWFP). A key aspect of the NWFP is a system of land use designation (LUD) in which spatially explicit zones are managed according to a single or dominant management priority (Charnley, 2006). For example, wilderness areas are designated as “Congressionally Withdrawn” and are thus protected from timber harvest, while “Matrix Lands” are those on which timber harvest is concentrated. The various LUDs, along with interspersed state, private and other lands, form a mosaic of ownership and management priorities that are manifested as disturbance patterns in the forest landscape. And so, the research question I’ll be addressing is: How do land use designations and ownership influence patterns of disturbance in Willamette National Forest?
2. Datasets:
I’ll be relying primarily on a Landsat imagery time-series (30 meter spatial resolution, 1985-2012) which has been processed using a change-detection algorithm called LandTrendr (Kennedy et al., 2010). Outputs from LandTrendr include disturbance patches categorized by agent of change (e.g., clear-cut, partial harvest, etc.) as well as their timing, duration and magnitude. This data will be clipped to the boundary of Willamette National Forest. To structure my analysis, I’ll be using vector data representing the administrative forest boundaries, and the LUDs and ownerships within them.
3. Hypotheses:
My general hypothesis is that patterns of disturbance will vary according to land use designation across space and time. For example, on Matrix Lands, I expect to see spatial clustering of clear-cuts that will increase during the period of the NWFP’s implementation (from 1994 onward), while on Adaptive Management Areas, I expect to see significantly fewer, more dispersed clearcuts, but increases in partial harvests.
4. Approach:
I will analyze spatial patterns of clear-cut and partial harvest disturbance patches within each LUD (e.g., clustering), as well as the spatial characteristics of these disturbance patches (e.g., edge-to-area ratio). My analysis will be done primarily in ArcGIS, but may also include Python scripting, statistical analysis in R, or “patch analysis” using FRAGSTATS.
5. Expected outcome:
I will produce maps and graphs of disturbance patterns by LUD over time. Hopefully this will help visualize whether or not the NWFP has been implemented as intended.
6. Significance:
In the Pacific Northwest, forest governance is shaped largely by the federally mandated Northwest Forest Plan (NWFP), which initiated a momentous shift in forest management priorities; from the provision of sustained timber harvest to protection of ecosystems (Thomas, 2006). The NWFP is implemented through an adaptive management strategy that must identify high priority inventory and monitoring objectives needed to assess the plan’s effectiveness over time (FEMAT, 1993). Ideally, this project and my overall research will contribute to this ongoing assessment.
7. Experience levels with…
ArcGIS = high
Modelbuilder, Python = medium
R = low
References:
Charnley, S., & Pacific Northwest Research Station. (2006). Northwest Forest Plan, the first 10 years (1994-2003) : Socioeconomic monitoring results (General technical report PNW ; 649). Portland, OR: U.S. Dept. of Agriculture, Forest Service, Pacific Northwest Research Station.
Kennedy, R. E., Z. Yang, and W. B. Cohen. 2010. Detecting trends in forest disturbance and recovery using yearly Landsat time series: 1. LandTrendr – Temporal segmentation algorithms. Remote Sensing of Environment 114:2897-2910.
Thomas, J., Franklin, J., Gordon, J., & Johnson, K. (2006). The Northwest Forest Plan: Origins, Components, Implementation Experience, and Suggestions for Change. Conservation Biology, 20(2), 277-287.
Report of the Forest Ecosystem Management Assessment Team (FEMAT, 1993)