Dwarf Blackgum (Nyssa sylvatica) Contains Datable Fire Scars that Complement an Existing Fire History

Thomas Saladyga

doi:10.3390/fire2040061

Abstract

Blackgum (Nyssa sylvatica) is a “consummate subordinate” hardwood tree species consigned to the mid-canopy of many eastern North American forests. Despite its wide distribution and ecological amplitude, blackgum is an underutilized tree species in fire history reconstructions within its range. In this study, I analyzed cross-section samples collected from 19 fire-scarred blackgum trees at a dry, nutrient-poor ridgetop study area in northeastern Pennsylvania. All but two of these samples were successfully crossdated, each containing between one and six fire scars. Fires recorded by blackgum occurred frequently, with site-level mean fire intervals between approximately three and five years. There was an increase in blackgum growth within two years following fire events, but this increase was not statistically significant and it was dependent on local fire regime characteristics. In addition, the blackgum fire-scar data increased the temporal and spatial resolution of an existing local fire history. These results provide evidence for the potential use of blackgum in fire history reconstructions, but applications may be limited by tree age, complacent growth that prevents crossdating, and the degree of rot resistance after scarring.

Highlights

Blackgum (Nyssa sylvatica Marsh.), known alternatively as black tupelo or sour gum, is a NorthAmerican hardwood tree species with a geographic range extending from Maine to east Texas and from southern Ontario to central Florida [1,2]
These results provide evidence for the potential use of blackgum in fire history reconstructions, but applications may be limited by tree age, complacent growth that prevents crossdating, and the degree of rot resistance after scarring
A raw ring-width chronology was generated for the study area as a whole and for Spring Mountain East (SME) and Spring Mountain Central (SMC)—only one blackgum sample collected at Spring Mountain West (SMW) was crossdated

Summary

Introduction

Blackgum (Nyssa sylvatica Marsh.), known alternatively as black tupelo or sour gum, is a North. In addition to its extensive range and ecological amplitude, blackgum is one of the longest-lived hardwood species in eastern North America, capable of reaching ages >600 years [9]. Fire scars embedded in the annual growth rings of trees are commonly used to reconstruct and infer historical fire regime characteristics, including the frequency, spatial extent, severity, and season of fire occurrence [10]. In a rare instance of sampling hardwood species other than oak in a fire history study, Silver and others [15] dated fire-scarred sourwood (Oxydendrum arboreum (L.). This brief report addresses questionsLam.), regarding the use blackgum fire history studies:. This brief report addresses four questions regarding the use of blackgum in fire history studies:

Materials and Methods

Blackgum Growth and Fire-Scar Data

Conclusions