Locating Forest Management Units Using Remote Sensing and Geostatistical Tools in North-Central Washington, USA.

Palaiologos Palaiologou,John Hogland,Kostas Kalabokidis,Maureen Essen

doi:10.3390/s20092454

Abstract

In this study, we share an approach to locate and map forest management units with high accuracy and with relatively rapid turnaround. Our study area consists of private, state, and federal land holdings that cover four counties in North-Central Washington, USA (Kittitas, Okanogan, Chelan and Douglas). This area has a rich history of landscape change caused by frequent wildfires, insect attacks, disease outbreaks, and forest management practices, which is only partially documented across ownerships in an inconsistent fashion. To consistently quantify forest management activities for the entire study area, we leveraged Sentinel-2 satellite imagery, LANDFIRE existing vegetation types and disturbances, monitoring trends in burn severity fire perimeters, and Landsat 8 Burned Area products. Within our methodology, Sentinel-2 images were collected and transformed to orthogonal land cover change difference and ratio metrics using principal component analyses. In addition, the Normalized Difference Vegetation Index and the Relativized Burn Ratio index were estimated. These variables were used as predictors in Random Forests machine learning classification models. Known locations of forest treatment units were used to create samples to train the Random Forests models to estimate where changes in forest structure occurred between the years of 2016 and 2019. We visually inspected each derived polygon to manually assign one treatment class, either clearcut or thinning. Landsat 8 Burned Area products were used to derive prescribed fire units for the same period. The bulk of analyses were performed using the RMRS Raster Utility toolbar that facilitated spatial, statistical, and machine learning tools, while significantly reducing the required processing time and storage space associated with analyzing these large datasets. The results were combined with existing LANDFIRE vegetation disturbance and forest treatment data to create a 21-year dataset (1999–2019) for the study area.

Highlights

In the USA, the annual average number of large fires has tripled and the average fire size increased by at least six times since the 1970s [1]
The bulk of analyses were performed using the Rocky Mountain Research Station (RMRS) Raster Utility toolbar that facilitated spatial, statistical, and machine learning tools, while significantly reducing the required processing time and storage space associated with analyzing these large datasets
PCAdiv were correlated with the PCAsub and as a result, they were not used in the analysis

Summary

Introduction

In the USA, the annual average number of large fires has tripled and the average fire size increased by at least six times since the 1970s [1]. The fire deficit, described as the difference between the historical rate of burning and the current rate of fire frequency plus mechanical treatments, in large contributes to higher density forests with larger quantities of fuels [2]. Owing to this circumstance, private, state, and Federal agencies within the USA face ever-increasing fire suppression costs. This increase in wildfire frequency, size, suppression costs, and other factors has helped promote fuel management in both wildlands and home ignition zones inside the Wildland-Urban Interface (or in both during cross-boundary projects) as an available short term option compared to suppression alone to cope with wildfire related issues [5,6,7]

Objectives

Methods

Results

Discussion

Conclusion