Natural conifer regeneration patterns in temperate forests across the Inland Northwest, USA
Natural regeneration patterns of conifer species were studied. Seedling regeneration follows patterns responding to stand structure and site condition factors along shade and drought tolerance gradients. Our findings can assist in adaptive forest management for maintaining sustainable regeneration and plant biodiversity.
Seedling regeneration can vary with stand factors of overstory trees and understory non-tree vegetation and site conditions.
Natural seedling regeneration patterns of coniferous species were investigated using Forest Inventory and Analysis (FIA) data of 10 common species across the Inland Northwest, USA.
Zero-inflated negative binomial models were developed to understand the responses of natural regeneration to stand factors and site conditions.
Seedling occurrence varies along shade and drought tolerance gradients responding to stand structure and site conditions. Two moderate shade-tolerant species of different drought tolerance contributed as a transition. Strong response patterns were revealed for seedling density, in which seedling density was improved with the presence of conspecific trees while limited by competition, especially from the understory vegetation layer.
Overstory structure and understory vegetation could improve or hinder natural regeneration of coniferous tree species given different shade tolerance and site conditions. Our findings can be effectively implemented in adaptive forest management for maintaining sustainable regeneration of specific conifers in broad temperate mixed forests.
KeywordsNatural regeneration pattern Coniferous tree species Stand structure Understory non-tree vegetation Site conditions Forest Inventory and Analysis
The authors would like to sincerely thank FIA for sharing sampling data and Dr. John Shaw for the help in maximum stand density index calculation. The efforts of editors and anonymous reviewers are highly appreciated.
This material is based upon work that is supported by the University of Idaho, College of Natural Resources and the National Institute of Food and Agriculture, US Department of Agriculture, McIntire Stennis project under accession number 1008381.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
- Adams DL, Mahoney RL (1991) Effects of shade and competing vegetation on growth of western redcedar regeneration. West J Appl For 6:21–22Google Scholar
- Bailey RG (1995) Description of ecoregions of the United States, 2nd ed. Misc. Publ. 1391. USDA Forest Service, Washington, DC, p 108Google Scholar
- Bilan MV (1960) Stimulation of cone and seed production in pole-size loblolly pine. For Sci 6:207–220Google Scholar
- Callaway RM (2007) Positive interactions and interdependence in plant communities. Houten, Netherlands: Springer NetherlandsGoogle Scholar
- Curtis RO (1982) A simple index of stand density for Douglas-fir. For Sci 28:92–94Google Scholar
- Edwards DGW (1976) Seed physiology and germination in western hemlock. In: Atkinson WA, Zasoski RJ (eds) Proceedings, Western Hemlock Management Conference. University of Washington, Seattle, Washington, pp 87–102Google Scholar
- Ferguson DE, Stage AR, Boyd RJ (1986) Predicting regeneration in the grand fir-cedar-hemlock ecosystem of the Northern Rocky Mountains. For Sci 32:1–42Google Scholar
- FIA (2017) Forest Inventory and Analysis Database. U.S. Department of Agriculture, Forest Service, Northern Research Station, St. PaulGoogle Scholar
- Fortin MJ, Dale MRT (2005) Spatial analysis-a guide for ecologists. Cambridge University PressGoogle Scholar
- Heath LS, Hansen MH, Smith JE, Miles PD (2008) Investigation in calculating tree biomass and carbon in the FIADB using a biomass expansion factor approach. Forest Inventory and Analysis (FIA) Symposium; October 21–23. UT, Park City, p 2008Google Scholar
- Jackman S, Tahk A, Zeileis A, Maimore C, Fearon J (2015) Package ‘pscl’: Political Science Computational Laboratory, Stanford University. URL http://pscl.stanford.edu/
- Jurgensen MF, Harvey AE, Graham RT, Page-Dumroese DS, Tonn JR, Larsen MJ, Jain TB (1997) Impacts of timber harvesting on soil organic matter, nitrogen, productivity, and health of Inland Northwest forests. For Sci 43(2):234–251Google Scholar
- Larson MM, Schubert GH (1969) Effect of osmotic water stress on germination and initial development of ponderosa pine seedlings. For Sci 15:30–36Google Scholar
- Li MH, Du Z, Pan HL, Yan CF, Xiao WF, Lei JP (2012) Effects of neighboring woody plants on target trees with emphasis on effects of understorey shrubs on overstorey physiology in forest communities: a mini-review. Commun Ecol 13:117–128. https://doi.org/10.1556/ComEc.13.2012.1.14 CrossRefGoogle Scholar
- Long JN, Shaw JD (2005) A density management diagram for even-aged ponderosa pine stands. West J Appl For 20:205–215Google Scholar
- Mahalovich MF, Burr KE, Foushee DL (2006) Whitebark pine germination, rust resistance, and cold hardiness among seed sources in the Inland Northwest: planting strategies for restoration. USDA Forest Service Proceedings RMRS-P-43Google Scholar
- Monserud RA, Ledermann T, Sterba H (2005) Are self-thinning constraints needed in a tree-specific mortality model? For Sci 50:848–858Google Scholar
- Noble DL, Alexander RR (1977) Environmental factors affecting natural regeneration Engelmann spruce in the Central Rocky Mountains. For Sci 23:420–429Google Scholar
- R core team (2017) R: a language and environment for statistical computing. R Foundation for Statistical Computing, Vienna, Austria. http://www.R-project.org/
- Shaw JD (2000) Application of stand density index to irregularly structure stands. West J Appl For 15:40–42Google Scholar
- Stage AR, Salas C (2007) Interactions of elevation, aspect, and slope in models of forest species composition and productivity. For Sci 53:486–492Google Scholar
- Vandenberghe C, Freléchoux F, Gadallah F, Buttler A (2006) Competitive effects of herbaceous vegetation on tree seedling emergence, growth and survival: does gap size matter? J Veg Sci 17:481–488. https://doi.org/10.1111/j.1654-1103.2006.tb02469.x CrossRefGoogle Scholar