Influence of Forest Management on Acorn Production in the Southeastern Missouri Ozarks: Early Results of a Long-Term Ecosystem Experiment

Matthew G Olson,Randy G Jensen,Alexander J Wolf

doi:10.4236/ojf.2015.55051

Abstract

Since acorn production is a foundational process of ecosystems dominated by oaks, understanding the impact of forest management practices on acorn production is critical to the sustainable management of oak forests. This investigation addressed the impact of even-aged management (EAM), uneven-aged management (UAM), and no-harvest management (NHM) on the production of mature, sound acorns over an 18-year period (1993-2010) of a long-term, landscape-scale forest management experiment in the Missouri Ozarks. Forest management impacts were investigated at two operational scales: the multi-stand compartment and the stand. We hypothesized that acorn production at both scales would be lower under active management (EAM and UAM) than NHM on these oak-dominated landscapes. Acorn production (acorns/ha/year) of red oaks (mainly black oak (Quercus velutina) and scarlet oak (Q. coccinea)) at the compartment level was lower under active management than NHM during the post-treatment period (1997-2010), but not for white oaks (mainly white oak (Q. alba) and post oak (Q. stellata)), which was largely a result of greater abundance and preferential harvesting of mature red oaks. At the stand scale, acorn production following either intermediate thinning or single-tree selection was comparable to yields observed in untreated stands suggesting that partial overstory removal can be implemented for harvesting timber and other silvicultural objectives without sacrificing acorn production. In many oak-dominated forests, active management will be necessary to mitigate future losses of acorn production driven by oak decline, succession, and climate change, including approaches for sustaining oak recruitment and acorn production.

Highlights

Acorn production is a foundational process of oak (Quercus) forest ecosystems
During the pre-treatment period (1993-1995), mean annual acorn yield of red oak species varied from 1100 acorns/ha in 1993 among sites designated for even-aged management (EAM) to 178,000 acorns/ha in 1994 among sites designated for uneven-aged management (UAM) (Figure 2(a))
Over the first post-treatment period of Missouri Ozark Forest Ecosystem Project (MOFEP) (1997-2010), acorn production by red oak species ranged from a high of 133,000 acorns/ha in 1997 under no-harvest management (NHM) to zero acorns collected in 2008 across the entire network of hard mast

Summary

Introduction

Acorn production is a foundational process of oak (Quercus) forest ecosystems. Aside from its obvious importance in the sexual reproduction of oaks, acorns are a primary food source of many vertebrate and invertebrate species. Nearly 100 bird and mammal species consume acorns in North America (Martin et al, 1961). Acorn production can influence ecosystems in complex ways through trophic interactions (Ostfeld, 2002) and is considered a keystone resource (Wolff, 1996). The inter-annual variability in acorn production influences the dynamics of wildlife populations, including numerous ecologically important bird and mammal species (McShea & Healy, 2002). Acorn production has even been linked to gypsy moth outbreaks (Elkinton et al, 1996) and Lyme’s disease infection (Jones et al, 1998)

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Discussion

Conclusion