Chemistry and ectomycorrhizal communities of coarse wood in young and old-growth forests in the Cascade Range of Oregon

Abstract

Coarse wood provides important ecosystem structure and function such as water and nutrient storage and critical habitat for the conservation of a variety of organisms, including ectomycorrhizal (EM) fungi. The chemistry and EM communities were compared in coarse wood samples collected from two advanced decay stages of logs in 12 paired young and old-growth stands in the Oregon Cascade Range. Average total C and nonpolar extractives were higher in young stands (15–55 years) (mean = 53.38%, 95% CI of 52.48–54.27 and mean = 8.54%, 95% CI of 6.92–10.16, respectively) compared with old-growth stands (200–500 years) (mean = 51.22%, 95% CI of 49.67–52.77 and mean = 6.75%, 95% CI of 5.88–7.62, respectively). Averages for total and extractable P were higher in old-growth stands (mean = 0.03%, 95% CI of 0.02–0.04 and mean = 82.91, 95% CI of 52.24–113.57, respectively) compared with young stands (mean = 0.02%, 95% CI of 0.02–0.02 and mean = 56.17, 95% CI of 45.84–66.50, respectively). Average pH and total N were highest in logs in the most advanced decay stage (mean = 4.17, 95% CI of 3.97–4.38 and mean = 0.35%, 95% CI of 0.29–0.40, respectively). No differences between log decay class or stand age were detected for water-soluble extractives, hemicellulose plus cellulose (or acid-hydrolyzable fraction), or acid-unhydrolyzable residue. Observed differences in average wood property values between decay stages and between young and old-growth stands were small and, although statistically significant, may not reflect an important difference in EM fungal habitat. EM communities were similar between young and old-growth stands and between logs in decay classes 4 and 5. Results suggest that down wood in advanced decay stages provides similar habitat for EM fungi in both old-growth and young, managed stands.

Carbon storage in old-growth and second growth fire-dependent western larch (Larix occidentalis Nutt.) forests of the Inland Northwest, USA

“…Coarse woody debris is an important ecosystem component of coniferous forest structure and function, providing C, water, and nutrient storage and critical habitat for a variety of organisms (Elliott et al, 2007;Harmon et al, 1986). In this study, the relatively limited quantities of CWD reflects the unique environment of these forests, including low productivity from cool temperatures, moisture limitation, and, to a lesser degree, the role of fire in these dry forests of the interior West as contrasted with more mesic coastal ecosystems (Harmon et al, 1986;Tinker and Knight, 2000).…”

Ectomycorrhizal fungal hyphae communities vary more along a pH and nitrogen gradient than between decayed wood and mineral soil microsites

“…We were interested in the potential niche preferences of ECM fungi, which are directly responsible for nutrient acquisition by their woody plant hosts (Read and Perez-Moreno 2003). Coarse woody debris in varying stages of decay has been shown to be effective ECM fungal habitat (Christy et al 1982, Elliott et al 2007). Several studies have documented a clear difference in the frequency and abundance of ECM fungal root tips found in logs versus forest floors (Goodman and Trofymow 1998;Tedersoo et al 2003;Iwań ski and Rudawska 2007;Tedersoo et al 2008).…”

Decomposition and change in N and organic composition of small-diameter Douglas-fir woody debris over 23 years

“…Previous studies have also revealed what appear to be contrasting patterns of change in organic components during decomposition of conifer CWD. Logs of larger diameter generally show little change in organic composition in the early stages of decay, consistent with effects of white-rot fungi, whereas the later stages are dominated by brown-rot fungi, leaving highly decayed reddish-brown residues consisting mainly of modified lignin (Means et al 1992;Preston et al 2006;Elliott et al 2007). The latter contribute to high spatial variability in the organic composition of forest floor (Preston et al 2002) and formation of organic horizons (Lignic Folisols) dominated by brown-rot residues (Fox and Tarnocai 2011).…”