TY - JOUR T1 - Challenges and opportunities for maintaining ponderosa pine forests in the southwestern U.S. JF - Tree Planters’ Notes Y1 - 2019 A1 - T.E Kolb A1 - A. Dixit A1 - O. Burney AB -

Deforestation caused by wildfire and bark beetle attacks in southwestern ponderosa pine (Pinus ponderosa Douglas ex P. Lawson & C. Lawson.) forests have increased over the past century due to climate warming. Continued warming is expected to increase deforestation. Ponderosa pine regeneration after deforestation often is inadequate in the region. Opportunities exist for active management to mitigate deforestation. First, planting can promote reforestation, but survival of planted seedlings is generally poor and highly variable among sites. The region needs more research about improving early seedling performance. Secondly, improving aridity adaptation of planted seedlings by seed source selection may improve outplanting performance. New common garden studies of seedling aridity adaptation of Arizona and New Mexico provenances suggest genetic variation in aridity adaptation among populations. Early results show genetic variation in survival under extreme drought conditions. Greenhouse experiments are investigating genetic variation in mechanisms of aridity tolerance. Promotion of forest recovery using these emerging approaches will be critical for sustaining forests in the increasingly arid southwestern U.S.

VL - 62:104-112 UR - https://rngr.net/publications/tpn/62-1-2/challenges-and-opportunities-for-maintaining-ponderosa-pine-forests-in-the-southwestern-united-states/?searchterm=kolb ER - TY - JOUR T1 - Local biotic adaptation of trees and shrubs to plant neighbors. JF - Okios Y1 - 2017 A1 - Grady, K.C. A1 - Wood, T. E. A1 - Kolb, T. E. A1 - Hersch-Green, E. A1 - Shuster, S.M. A1 - Gehring, C. A. A1 - Hart, S.C. A1 - Allan, G.J. A1 - T. G. Whitham AB -

Natural selection as a result of plant–plant interactions can lead to local biotic adaptation. This may occur where species frequently interact and compete intensely for resources limiting growth, survival, and reproduction. Selection is demonstrated by comparing a genotype interacting with con‐ or hetero‐specific sympatric neighbor genotypes with a shared site‐level history (derived from the same source location), to the same genotype interacting with foreign neighbor genotypes (from different sources). Better genotype performance in sympatric than allopatric neighborhoods provides evidence of local biotic adaptation. This pattern might be explained by selection to avoid competition by shifting resource niches (differentiation) or by interactions benefitting one or more members (facilitation). We tested for local biotic adaptation among two riparian trees, Populus fremontii and Salix gooddingii, and the shrub Salix exigua by transplanting replicated genotypes from multiple source locations to a 17 000 tree common garden with sympatric and allopatric treatments along the Colorado River in California. Three major patterns were observed: 1) across species, 62 of 88 genotypes grew faster with sympatric neighbors than allopatric neighbors; 2) these growth rates, on an individual tree basis, were 44, 15 and 33% higher in sympatric than allopatric treatments for P. fremontii, S. exigua and S. gooddingii, respectively, and; 3) survivorship was higher in sympatric treatments for P. fremontii and S. exigua. These results support the view that fitness of foundation species supporting diverse communities and dominating ecosystem processes is determined by adaptive interactions among multiple plant species with the outcome that performance depends on the genetic identity of plant neighbors. The occurrence of evolution in a plant‐community context for trees and shrubs builds on ecological evolutionary research that has demonstrated co‐evolution among herbaceous taxa, and evolution of native species during exotic plants invasion, and taken together, refutes the concept that plant communities are always random associations.

VL - 126 UR - https://onlinelibrary.wiley.com/doi/full/10.1111/oik.03240 IS - 4 ER - TY - CONF T1 - Southwestern white pine performance across an elevational gradient. T2 - National Silviculture Workshop Y1 - 2017 A1 - DaBell,J A1 - K Waring A1 - TE Kolb A1 - AV Whipple JF - National Silviculture Workshop T3 - National Silviculture Workshop CY - Flagstaff, Arizona, USA ER - TY - CONF T1 - Southwestern white pine performance across an elevational gradient. T2 - North American Forest Ecology Workshop Y1 - 2017 A1 - DaBell,J A1 - K Waring A1 - TE Kolb A1 - AV Whipple AB -

DaBell, J., Waring, K., Kolb, T. and Whipple, A. 2017. Southwesternwhite pine performance across an elevational gradient. North American Forest Ecology Workshop, June 18-22, 2017, Edmonton, Canada. Also presented at the National Silviculture Workshop, July 18-20, 2017, Flagstaff, AZ.

JF - North American Forest Ecology Workshop T3 - North American Forest Ecology Workshop CY - Edmonton Canada VL - 2017 N1 - [Original String]:DaBell, J., Waring, K., Kolb, T. and Whipple, A. 2017. Southwestern white pine performance across an elevational gradient. North American Forest Ecology Workshop, June 18-22, 2017, Edmonton, Canada. Also presented at the National Silviculture Workshop, July 18-20, 2017, Flagstaff, AZ. ER - TY - JOUR T1 - Genetic variation in Pinus strobiformis growth and drought tolerance from southwestern US populations. JF - Tree physiology Y1 - 2016 A1 - Goodrich,Betsy A A1 - Waring,Kristen M A1 - Kolb,Thomas E KW - Adaptation, Physiological KW - Droughts KW - Genetic Variation KW - Pinus KW - Southwestern United States KW - Trees AB -

The persistence of some tree species is threatened by combinations of novel abiotic and biotic stressors. To examine the hypothesis that Pinus strobiformis Engelm., a tree threatened by an invasive forest pathogen and a changing climate, exhibits intraspecific genetic variation in adaptive traits, we conducted a common garden study of seedlings at one location with two watering regimes using 24 populations. Four key findings emerged: (i) growth and physiological traits were low to moderately differentiated among populations but differentiation was high for some traits in water-stressed populations; (ii) seedlings from warmer climates grew larger, had higher stomatal density and were more water-use efficient (as measured by the carbon isotope ratio) than populations from colder climates; (iii) seedlings from the northern edge of the species' distribution had lower water-use efficiency, higher stomatal conductance, slower growth and longer survival in a lethal drought experiment compared with seedlings from more southern populations; and (iv) based on non-metric multidimensional scaling analyses, populations clustered into southern and northern groups, which did not correspond to current seed transfer zones. Our discovery of a clinal geographic pattern of genetic variation in adaptive traits of P. strobiformis seedlings will be useful in developing strategies to maintain the species during ongoing climate change and in the face of an invasive pathogen.

VL - 36 SN - 0829-318X UR - http://www.ncbi.nlm.nih.gov/sites/entrez?Db=pubmed&DbFrom=pubmed&Cmd=Link&LinkName=pubmed_pubmed&LinkReadableName=Related%20Articles&IdsFromResult=27344065&ordinalpos=3&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_RVDocSumhttp://www.ncbi. IS - 10 ER - TY - JOUR T1 - Local-Scale Drought Adaptation of Ponderosa Pine Seedlings at Habitat Ecotones JF - Forest Science Y1 - 2016 A1 - TE Kolb A1 - Grady,KC A1 - Mcettrick,MP A1 - Herrero,A AB - Abstract Understanding the magnitude and pattern of intraspecific variation in tree adaptation to drought is needed to evaluate forest capacity to respond to climate change and for management planning. This understanding is important for species growing at ecotonal sites near the trailing edge of their geographic range where impacts of climate warming are predicted to be most severe. We used a greenhouse common garden to investigate phenotypic variations in growth, drought-adaptive structural traits (e.g., wood specific gravity, shoot-root ratio, and specific leaf area), and survival during experimental drought in seedlings of ponderosa pine (Pinus ponderosa Doug. Ex. Laws) sampled from 17 sites in northern Arizona over gradients of elevation, precipitation, and soil parent material. Phenotypic variation was significant in most seedling traits, and the most variation occurred among maternal families within site populations. Growth rate was negatively correlated with wood specific gravity. The large amount of phenotypic variation within populations suggests the potential for future evolution of stress tolerance in trailing-edge populations. The strongest geographic pattern in phenotypic variation was a negative relationship between seedling biomass allocation to roots and precipitation of the population site. Families with the longest survival in a lethal drought experiment tended to come from low-elevation, drier sites. VL - 62 UR - http://www.ingentaconnect.com/content/saf/fs/pre-prints/content-forsci16049 ER - TY - JOUR T1 - Long-term thinning alters ponderosa pine reproduction in northern Arizona. JF - Forest Ecology and Management Y1 - 2016 A1 - Flathers,KN A1 - TE Kolb A1 - Bradford,JB A1 - Waring,KM A1 - Moser,WK VL - 374 N1 - [Original String]:Flathers, K. N., Kolb, T. E., Bradford, J. B. Waring, K. M. and Moser, W. K. (2016). Long-term thinning alters ponderosa pine reproduction in northern Arizona. Forest Ecology and Management 374:154-165. ER - TY - CONF T1 - Southwestern white pine seedling tolerances to a changing climate: early results from common gardens across an elevational gradient. T2 - Society of American Foresters National Convention Y1 - 2016 A1 - DaBell,J A1 - K Waring A1 - TE Kolb A1 - AV Whipple A1 - Madison,WI JF - Society of American Foresters National Convention T3 - Society of American Foresters National Convention CY - Madison, Wisconsin, USA VL - 2016 N1 - [Original String]:DaBell, J., Waring, K., Kolb, T., and Whipple, A. 2016. Southwestern white pine seedling tolerances to a changing climate: early results from common gardens across an elevational gradient. Society of American Foresters National Convention, November 2-5, 2016, Madison, WI. ER - TY - CONF T1 - Sustaining southwestern white pine by combining experimental work and genomic tools. Y1 - 2016 A1 - Castilla,AR A1 - R Sniezko A1 - K Waring A1 - Cushman,S A1 - Eckert,A.J A1 - Flores,L A1 - Still,C A1 - Wehenkel,C A1 - Whipple,A A1 - Wing,M A1 - TE Kolb A1 - Goodrich,B.A. ER - TY - JOUR T1 - Conservative leaf economic traits correlate with fast growth of genotypes of a foundation riparian species near the thermal maximum extent of its geographic range . JF - Functional Ecology Y1 - 2013 A1 - Grady,KC A1 - Laughlin,DC A1 - Ferrier,SM A1 - TE Kolb A1 - Hart,SC A1 - GJ Allan A1 - TG Whitham VL - 27 N1 - [Original String]:Grady KC, Laughlin DC, Ferrier SM, Kolb TE, Hart SC, Allan GJ, Whitham TG. 2013. Conservative leaf economic traits correlate with fast growth of genotypes of a foundation riparian species near the thermal maximum extent of its geographic range . Functional Ecology 27:427-438. ER - TY - JOUR T1 - Genetic variation in productivity of foundation riparian species at the edge of their distribution: implications for restoration and assisted migration in a warming climate . JF - Global Change Biology Y1 - 2011 A1 - Grady,KC A1 - Ferrier,SM A1 - TE Kolb A1 - Hart,SC A1 - Allan,GA A1 - TG Whitham VL - 17 N1 - [Original String]:Grady KC, Ferrier SM, Kolb TE, Hart SC, Allan GA, Whitham TG. 2011. Genetic variation in productivity of foundation riparian species at the edge of their distribution: implications for restoration and assisted migration in a warming climate . Global Change Biology 17:3724-3735. ER - TY - JOUR T1 - A conditional trophic cascade: birds benefit faster growing trees with strong links between predators and plants. JF - Ecology Y1 - 2010 A1 - Bridgeland,William T A1 - Beier,Paul A1 - Kolb,Thomas A1 - Whitham,Thomas G KW - Animals KW - Birds KW - Food Chain KW - Insecta KW - Predatory Behavior KW - Time Factors KW - Trees AB -

Terrestrial systems are thought to be organized predominantly from the bottom-up, but there is a growing literature documenting top-down trophic cascades under certain ecological conditions. We conducted an experiment to examine how arthropod community structure on a foundation riparian tree mediates the ability of insectivorous birds to influence tree growth. We built whole-tree bird exclosures around 35 mature cottonwood (Populus spp.) trees at two sites in northern Utah, USA, to measure the effect of bird predation on arthropod herbivore and predator species richness, abundance, and biomass, and on tree performance. We maintained bird exclosures over two growing seasons and conducted nondestructive arthropod surveys that recorded 63652 arthropods of 689 morphospecies representing 19 orders. Five major patterns emerged: (1) We found a significant trophic cascade (18% reduction in trunk growth when birds were excluded) only at one site in one year. (2) The significant trophic cascade was associated with higher precipitation, tree growth, and arthropod abundance, richness, and biomass than other site-year combinations. (3) The trophic cascade was weak or not evident when tree growth and insect populations were low apparently due to drought. (4) Concurrent with the stronger trophic cascade, bird predation significantly reduced total arthropod abundance, richness, and biomass. Arthropod biomass was 67% greater on trees without bird predation. This pattern was driven largely by two herbivore groups (folivores and non-aphid sap-feeders) suggesting that birds targeted these groups. (5) Three species of folivores (Orthoptera: Melanoplus spp.) were strong links between birds and trees and were only present in the site and the year in which the stronger trophic cascade occurred. Our results suggest that this trophic system is predominately bottom-up driven, but under certain conditions the influence of top predators can stimulate whole tree growth. When the most limiting factor for tree growth switched from water availability to herbivory, the avian predators gained the potential to reduce herbivory. This potential could be realized when strong links between the birds and plant, i.e., species that were both abundant herbivores and preferred prey, were present.

VL - 91 SN - 0012-9658 UR - http://www.ncbi.nlm.nih.gov/sites/entrez?Db=pubmed&DbFrom=pubmed&Cmd=Link&LinkName=pubmed_pubmed&LinkReadableName=Related%20Articles&IdsFromResult=20380198&ordinalpos=3&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_RVDocSumhttp://www.ncbi. IS - 1 ER -