Treesearch

Lignin is an abundant and complex plant polymer that may limit litter decomposition, yet lignin is sometimes a minor constituent of soil organic carbon (SOC). Accounting for diversity in soil characteristics might reconcile this apparent contradiction. Tracking decomposition of a lignin/litter mixture and SOC across different North American mineral soils using lab and field incubations, here we show that cumulative lignin decomposition varies 18-fold among soils and is strongly correlated with bulk litter decomposition, but not SOC decomposition. Climate legacy predicts decomposition in...

The Central Hardwood and Appalachian regions have large expanses of previously forested, but now degraded agricultural or pastoral lands that have been reappropriated for the growth of hardwood plantings and orchards. Although fine hardwoods such as black walnut (Juglans nigra L.) and northern red oak (Quercus rubra L.) have been used for everything from flooring to finely crafted furniture to orchards for nut production, gaps exist in our knowledge regarding the most efficient methods of growing these prized hardwoods.

Agriculture and food systems are foundational in delivering ecosystem goods and services. There are significant opportunities for landscape architects to engage in the planning and design of regenerative agricultural systems. Particularly when conducted at a land grant university, design studio courses can prepare future landscape architects to work collaboratively toward more resilient and equitable food systems under a changing climate. This paper presents a studio course pedagogy for designing agroforestry systems in a rural county by linking research to extension through student design...

White pine blister rust (WPBR) is caused by the non- native fungus, Cronartium ribicola, a devastating pathogen of North American five-needle pines. Over the past century and a quarter, this pathogen has proven to be one of the most damaging agents of five-needle white pines (Geils et al. 2010; Schoettle et al. 2022) and is the primary factor in the recent ESA listing of whitebark pine (Pinus albicaulis, WBP) as threatened in the USA. Whitebark pine is a high-elevation species of western mountain ecosystems that is highly susceptible to WPBR. Since its detection in the Rocky Mountains of...

Interspecific hybridization plays a key role in the evolution of novel fungal pathogens, and when it occurs between native and invasive species, can lead to potentially serious consequences. In this study, we examined the temporal and spatial distribution of a recently detected hybrid (Cronartium x flexili) of two tree pathogens, invasive to North America Cronartium ribicola and native Cronartium comandrae. In total, 726 and 1452 aecia from 178 Pinus contorta ssp. latifolia and 357 Pinus flexilis trees were collected from 26 sites in four national forests in 2019–2021. Using morphological...

The High-5 comprise a subset of a unique group of related white pine species in the subgenus Strobus that grow across the high mountains of western North America. They include whitebark pine (Pinus albicaulis), limber pine (P. flexilis), southwestern white pine (P. strobiformis), Rocky Mountain bristlecone pine (P. aristata), Great Basin bristlecone pine (P. longaeva), and foxtail pine (P. balfouriana) (Fig. 1). These species grow in small groups on ridges as well as components of extensive forest communities. They have a disproportionally large effect on ecosystem functioning and biodivers...

Since the development of contemporary stocking techniques a century ago, the combination of climatic, atmospheric, financial, and social factors that determine forest management strategies have changed, altering aspen stand dynamics in the western Great Lakes, USA. Despite this, aspen management is still informed by 1970s management guides that are based on 1920s inventories; hence, a century exists between the data that underlie current management guidelines and current stand conditions. We hypothesized that current aspen stands may support higher stocking and height growth than nearly a...

Researchers have debated the relative importance of environmental versus Indigenous effects on past fire regimes in eastern North America. Tree-ring fire-scar records (FSRs) provide local-resolution physical evidence of past fire, but few studies have spatially correlated fire frequency from FSRs with environmental and anthropogenic variables. No study has compared FSR locations to Native American settlement features in the eastern United States. We assess whether FSRs in the eastern US are located near regions of past Native American settlement. We also assess relationships between...

Round timber and wood products are measured, sorted, and graded at different stages in the wood-value chain starting already at the stem level in the forest. This chapter gives an overview of grading methodologies and techhniques for the measurement and grading of round timber, sawn timber, veneer, and wood-panel products. The section concerning round timber focuses on the grading and sorting of logs for sawmill and veneer production. For sawn timber, visual and strength grading are discussed, for both the European and the North American markets. Techniques for measurement and process...