LANDIS 4.0, A New Generation Computer Simulation Model for Assessing Fuel Management Effects on Fire Risk in Eastern U.S. Forest Landscapes Hong S. He University of Missouri-Columbia

Acknowledgements Original Design: David Mladenoff LANDIS 4.0 Dynamic Design: Hong He  Succession/Dispersal Module  David Mladenoff, Hong He  Fire Module  Jian Yang, Hong He, Eric Gustafson  Wind Module  David Mladenoff, Hong He  Harvest Module  Eric Gustafson, Stephen Shifley, Kevin Nimerfro, David Mladenoff, Hong He  Fuel Module  Hong He, Bo Shang, Thomas Crow, Eric Gustafson, Stephen Shifley  Biological Disturbance Module  Brian Sturtevant, Eric Gustafson, Wei Li, Hong He  LANDIS 4.0 Programming  Vera W. Li, Jian Yang, Bo Shang, and Hong He Funding Supports for LANDIS 4.0 Development  USFS North Central Research Station

Introduction See reviews by Keane et al (Ecol. Model. 179) and Mladenoff (Ecol. Model. 180, 2004)

LANDIS Landscape Disturbance and Succession ‘Stochastic cellular automaton’ Raster-based  Complex spatial dynamics computationally possible  Infinite aggregation and dissolution of patches Spatial Scales Functional extent 100s ha – 10 7 ha Functional resolution- cell size 10x10m - km 2 Temporal Scales  Current model time step is 10 yr, while a version of annual time step has been developed and is being used in Southern California. LANDIS simulates multiple disturbance and management processes in combination with the simulation of succession dynamics at the tree species level.

LANDIS 4.0 Model Dynamics Tree Species Establishment and Resprouting Species Level Competitive Succession and Dispersal Disturbance and Harvest Related Mortality Wind (top down) Fire (bottom up) Insect/Disease (specie/age specific) Harvest (specie/age specific) Fuel (Accumulation/reduction) Species age/size susceptibility Modify fine/coarse fuel Modify Specie and Age Cohorts Land type Shade tolerance Background mortality Longevity Dispersal distance Disturbance and Management Modified from Mladenoff 2004 Ecological Modelling

LANDIS Operational Design climate zone soil map DEM Multiple fire regimes: Ignition, size, cycle, spread, intensity and severity multiple species and age input maps output single species map year 0 year n reclassified vegetation type output disturbances species age Classes model input model simulation processes Environmental boundaries and constrains Site and species interactions succession, seeding, disturbance history, and disturbance interaction Harvest prescriptions: stands, management units, rotation size, species, and methods fire wind harvest Land type Insect/disease fuel Fine, coarse and life fuel Accumulation/decomposition Wind regimes: size, cycle, spread, intensity and severity Epicenter, frequency, size, Hosts, susceptibility, intensity, and severity

LANDIS 4.0 Software Design --Component-based SUCCESSI ON 1/O BDA I/O FIRE I/O FUEL I/O HARVE ST I/O User1 User2 Usern species name longevity maturity mortality growth dispersal sprouting fire tolerance shade tolerance internal design I/O WIND

Sites of LANDIS Applications Modified from Mladenoff 2004 Ecological Modelling

An Application in Missouri Central Hardwood Forests

Fuel and Fire Management Issues Over half a century fire suppression Increasing fire intensity Need for fuel management  Currently prescribed burning 0.06% per year for fuel reduction  How extensive should fuel treatment be expanded, 0.6%, 1.2%, or 2.4% per year?  Should coarse woody debris reduction be employed?  What are the effects of the combinations of fuel treatment size and method?

Simulation Design Treatment Size (percentage /yr) Treatment Method PB PB+ CWD Factorial Design of Fuel Treatments A B C D E F G H

Simulation Design Using existing data of species/age and land types Current fire regime under suppression  Mean fire size 3.5=ha, SD=1.8 ha  Fire cycle 300 yrs on southwestern slopes and 450 yrs on northeastern land types Harvest  Even/uneven aged harvesting on oldest forest (>100 yrs) and “thinning” on young forest (<30 yrs), 0.4% /yr

Statistical Analysis Each treatment was simulated to 200 years with 10 replicates Overall treatment effects were analyzed using multivariate analysis of variance (MANOVA) Treatment pair comparisons was analyzed using ANOVA Response variables:  percent pixels (% landscape)  simulated fire severity classes (1-5), with 4 severely stand damaging and 5 stand leveling fire  five age classes of four species group, black oak, white oak, shortleaf pine, and maple Seedling, sapling, pole, sawlog, and old-growth

Results and Discussion Simulated Fire and Species Dynamics

Results and Discussion Simulated Fuel Dynamics

Simulated Fires at Different Severities 200 year means Ground fire Severe damaging Stand leveling Medium damaging Low damaging

Simulated Fires at Different Severities 200 Year Dynamics Simulation Years Fire Severity Class Proportions (%)

Effects of Fuel Treatments on Fire Severity Landscape (%) AB CD E F G H A B C D E F G H A B C D EF G H A B C D E F G H A B C D E F G H Ground fire Severe damaging Stand leveling Medium damaging Low damaging

Simulated Age Class Compositions 200 year means Black oak Pine Maple White oak

Effects of Fuel Treatments on Species Age Compositions—Seedling/Sapling Black oakPine Maple White oak Landscape (%) B C D E F G H A B C D E F G H A B C D E F G H A

Effects of Fuel Treatments on Species Age Compositions—Old Growth Black oakPine Maple White oak Landscape (%) B C D E F G H A B C D E F G H A BC D E F G H A B C D E F G H A

Summaries Low and mid severity fires will change to severe stand damaging (class 4) or stand leveling (class 5) fires under the situation of limited fuel treatment (e.g., 0.6%/yr) in central hardwood forests. Fuel treatments reduce fire occurrence, prolong fire cycle, and reduce the high severity fires.  Fire cycles extend from current years to over 1,000 years depending upon treatment methods.  Total sites burned by high severity fires are reduced from 11% to 1% of the study area. Fuel treatment size exhibits threshold effects in the study area:  When treatment size is small (e.g., <0. 6% per year (treatment B), treatment methods have little effect in terms of reducing fire severity.

Summaries CWD reduction in combination with prescribed burning is more effective in reducing fire severity. The benefits of fuel treatment are not linearly related to the treatment effort.  Increasing treatment size from 1.2%/yr (F) to 2.4% /yr (G) reduces severe stand damaging fire from 2.4% to 0.5%. Further increasing treatment size to 4.8% (H) had only small effects (although statistically significant) on high severity fires. Thus planners and managers should consider a balanced approach in terms of treatment size and treatment effects. PB CWD Treatment F Treatment D Treatment effects

Summaries Fuel treatment effects on species composition and age class are statistically significant, except when treatment size is too small (e.g., <0.6%). However, such effects are secondary to the effects of fire suppression on species composition and age structure (result not shown). We showed that LANDIS is a effective model for evaluating long-term and large spatial effects for the identified scenarios. The actual future is only one realization of numerous possible scenarios that are beyond any simulation capacity. Thus LANDIS is not a predictive model. Nevertheless, the model is useful since the large-scale effects would otherwise be very difficult to assess.