Climate and interrelated tree regeneration drivers in mixed temperate–boreal forests

Abstract

Forest compositional shifts in response to climate change are likely to be initially detectable in the understory tree regeneration layer near species range limits. Because many factors in addition to climate, such as seedbed and soil characteristics, overstory composition, and interactions with other understory biota, drive tree regeneration trends, a thorough understanding of the relative importance of all variables as well as their interrelationships is needed. The range limits of several widespread temperate and boreal tree species overlap in the upper Great Lakes region, USA, thus facilitating an observational study over relatively short regional climate gradients. We used redundancy analysis and variation partitioning to quantify the unique, shared, and total explanatory power of four sets of explanatory variables. The results showed that all four variable sets (climate 9.5 %, understory environment 13.7 %, overstory composition 26.3 %, and understory biota 13.8 %) were significantly associated with tree regeneration compositional variation in mixed temperate-boreal forests. Partitioning also revealed high confounded or shared explanatory power, but also that each set contributed significant unique explanatory power not shared with other sets. Spatial patterning in regeneration composition was strongly related to broad scale environmental patterns, while the large majority of unexplained variation did not have a detectable spatial structure, suggesting factors with local scale variability. Future forest shifts across the landscape will depend not only on the rate and direction of climate change but also on how the strengths and interrelationships among other explanatory variables, such as overstory composition and understory biota, shift with a changing climate.

Climate change effects on northern Great Lake (USA) forests: A case for preserving diversity

“…8). The species that share a simulated increase or decrease across landscapes are consistent with empirical observations (Fisichelli et al 2012, Fisichelli et al 2013) and other modeling throughout the Great Lakes region (Iverson et al 2008, Xu et al 2009, Ravenscroft et al 2010.…”

“…The changes may exceed land-owners' ability to successfully manage forests with traditional forestry strategies. Within the northern Great Lakes region, vulnerability to climate change will likely depend on both latitude and proximity to the boreal-temperate transition zone (Fisichelli et al 2013). More specifically, adaptation to climate change may depend on the potential mix of species capable of providing ecosystem services under changing environmental conditions.…”

Association of Fruit and Seed Traits of Sapindus mukorossi Germplasm with Environmental Factors in Southern China

“…In particular, precipitation, temperature, and vegetation cover are important [34,35], which indicates that relatively few environmental conditions might be predominantly influential in determining S. mukorossi habitat preferences. In addition to S. mukorossi, other Sapindus species or varieties, such as S. delavayi, S. tomentosus, S. rarak, and S. rarak var.…”

Regeneration Responses to Management for Old-Growth Characteristics in Northern Hardwood-Conifer Forests

“…However, sugar maple, red maple, yellow birch, and American beech, surprisingly, showed enhanced seedling survival with increasing water deficit between 25 mm and 625 mm across their entire range [81]. These may be transient effects; if conditions become too dry or too wet seedling mortality may increase [83,84]. However, maintaining tree species diversity, as the FEMDP treatments did, at stand and landscape scales is an important strategy conferring ecosystem resilience to climate related stresses [19].…”