Assessing the effectiveness of landscape-scale forest adaptation actions to improve resilience under projected climate change

Abstract

Climate change will increase disturbance pressures on forested ecosystems worldwide. In many areas, longer, hotter summers will lead to more wildfire and more insect activity which will substantially increase overall forest mortality. Forest treatments reduce tree density and fuel loads, which in turn reduces fire and insect severity, but implementation has been limited compared to the area needing treatment. Ensuring that forests remain near their reference conditions will require a significant increase in the pace and scale of forest management. In order to assess what pace and scale may be required for a landscape at risk, we simulated forest and disturbance dynamics for the central Sierra Nevada, USA. Our modeling framework included forest growth and succession, wildfire, insect mortality and locally relevant management actions. Our simulations accounted for climate change (five unique global change models on a business-as-usual emissions pathway) and a wide range of plausible forest management scenarios (six total, ranging from less than 1% of area receiving management treatments per year to 6% per year). The climate projections we considered all led to an increasing climatic water deficit, which in turn led to widespread insect caused mortality across the landscape. The level of insect mortality limited the amount of carbon stored and sequestered while leading to significant composition changes, however, only one climate change projection resulted in increased fire over contemporary conditions. While increased pace and scale of treatments led to offsets in fire related tree mortality, managing toward historic reference conditions was not sufficient to reduce insect-caused forest mortality. As such, new management intensities and other adaptation actions may be necessary to maintain forest resilience under an uncertain future climate.

Quantitative methods for integrating climate adaptation strategies into spatial decision support models

“…Data used to characterize the carbon Metrics were derived from the LANDIS-II landscape simulation model (Scheller et al, 2007). In the current application, we apply the LANDIS-II model developed by Maxwell et al (2022) for the TCSI landscape. The model incorporated the NECN (Net Ecosystem Carbon and Nitrogen; Scheller et al, 2011) successional dynamics, the SCRPPLE (Social-Climate Related Pyrogenic Processes and their Landscape Effects; Scheller et al, 2019), the base biological disturbance agents (BDA; Sturtevant et al, 2004), and biomass harvest (Gustafson et al, 2000) extensions.…”

“…The model was run under the MIROC 8.5 climate change scenario over a 40 years period . The MIROC climate model was one of five recommended by California's Fourth Climate Change Assessment (Pierce et al, 2018) and, after extensive testing, was the only one to adequately represent recent exceptional droughts (2003)(2004)(2012)(2013)(2014)(2015) (Maxwell et al, 2022). Climate projections were downscaled using the MACA methodology (Abatzoglou and Brown, 2012) and are available through the USGS Geo Data Portal.…”

Forest Landscape Model Initialization with Remotely Sensed-Based Open-Source Databases in the Absence of Inventory Data

“…For most forest landscape models, the initial input data are vegetation maps containing information about certain characteristics of trees growing in the study area (species, age, biomass, etc.). One of the most widely used FLM models is the LANDIS-II (Landscape Disturbance and Succession Model) [11][12][13][14][15], which was developed to simulate changes in forest ecosystems based on disturbance and succession processes. The model takes into account various types of disturbances, such as fires, wind, and diseases, as well as succession processes such as tree growth and competition between them.…”

Integrating climate adaptation strategies in spatial decision support systems

“…LANDIS-II has been applied to a broad diversity of global landscapes and that work is documented in ~ 170 publications.For the TCSI project, LANDIS-II was run under the MIROC 8.5 climate stream over a40-year period (2020- 2060). The MIROC climate model was one of ve recommended by California's Fourth Climate Change Assessment (Pierce et al 2018) and, after extensive testing, was the only one to adequately represent recent exceptional droughts(2003)(2004)(2012)(2013)(2014)(2015) (Maxwell et al 2022). As such, it was associated with the highest level of re activity and represented the most likely climate future for the region, given current trends(Maxwell et al 2022).…”

“…The MIROC climate model was one of ve recommended by California's Fourth Climate Change Assessment (Pierce et al 2018) and, after extensive testing, was the only one to adequately represent recent exceptional droughts(2003)(2004)(2012)(2013)(2014)(2015) (Maxwell et al 2022). As such, it was associated with the highest level of re activity and represented the most likely climate future for the region, given current trends(Maxwell et al 2022). Climate projections were downscaled using the MACA methodology (Abatzoglou and Brown 2012) and are available through the USGS Geo Data Portal (https://cida.usgs.gov/gdp/).…”