Combined effects of an expanding shelterwood regeneration system and prescribed fire in oak dominated hardwood forest-preliminary results and progress

by

Skye Greenler and Mike Saunders

(SG, SM) Department of Forestry and Natural Resources, Purdue University, West Lafayette, IN (SG)Corresponding author: 715 State Street, West Lafayette, IN 47907; greenler@purdue.edu

Abstract – Many oak-dominated, eastern deciduous forests have very little oak seedling and sapling regeneration, and instead have an understory dominated by mesic or shade tolerant species such as sugar maple, American beech, and tulip poplar. This oak regeneration failure is a result of multiple factors, but changes in natural disturbance regimes, including a century of active fire suppression, is the major driver in these compositional shifts. In 2014, we implemented a large-scale study to investigate the combined, long-term effects of novel silvicultural systems and prescribed fire on oak regeneration, ecosystem resilience, and structural diversity in an oak dominated hardwood forest at NSA Crane in southern Indiana. Two replicates for this study were installed in 2014 and 2015 and we will instill a third in 2016. Each 50-75 acre replicate consists of five treatments: 1) 2-stage expanding group shelterwood; 2) 3-stage expanding group shelterwood; 3) 2-stage expanding group shelterwood with prescribed fire; 4) 3-stage expanding group shelterwood with prescribed fire; and 5) unharvested and unburned control. The 2014 prescribed fire averaged 240°C with a maximum recorded temperature of 820°C while the 2015 burn was patchier and averaged 200°C with a maximum temperature of 600°C. Fire intensity maps created from 30-50 thermocouples and 300-400 pyrometer paint tags per site, coupled with pre-burn fuel load and moisture data, will help to: i) advance development of custom fire models for southern Indiana, ii) quantify ecosystem responses at fine scales to prescribed fire intensity, and iii) quantify effects of prescribed fire intensity on timber quality.