TY - JOUR
T1 - The propagule doesn't fall far from the tree, especially after short-interval fire.
AU - Gill, Nathan
AU - Hoecker, Tyler
AU - Turner, Monica
N1 - Funding Information:
We thank K. Braziunas, W. Romme, D. Kulakowski, and two anonymous reviewers for comments that improved this manuscript, and C. Kluender, D. Abendroth, R. Steffens, J. Stephenson, K. Patronik, and L. Rios for assistance collecting data. We thank the University of Wyoming–National Park Service Research Station for logistical support, and Grand Teton National Park for facilitating this study. This work was completed under permit GRTE-2018-SCI-0039 and supported by a National Science Foundation (DEB-1719905) grant to MGT and a Michael T. Guyer Fellowship to NSG through the Department of Integrative Biology, University of Wisconsin–Madison. MGT also acknowledges support from the University of Wisconsin–Madison Vilas Trust. We declare no conflict of interest. NSG and MGT conceived the ideas and designed methods; NSG, TJH, and MGT collected, analyzed, and interpreted the data; and NSG led the writing of the manuscript, to which all authors contributed critically and gave approval for publication.
Funding Information:
We thank K. Braziunas, W. Romme, D. Kulakowski, and two anonymous reviewers for comments that improved this manuscript, and C. Kluender, D. Abendroth, R. Steffens, J. Stephenson, K. Patronik, and L. Rios for assistance collecting data. We thank the University of Wyoming–National Park Service Research Station for logistical support, and Grand Teton National Park for facilitating this study. This work was completed under permit GRTE‐2018‐SCI‐0039 and supported by a National Science Foundation (DEB‐1719905) grant to MGT and a Michael T. Guyer Fellowship to NSG through the Department of Integrative Biology, University of Wisconsin–Madison. MGT also acknowledges support from the University of Wisconsin–Madison Vilas Trust. We declare no conflict of interest. NSG and MGT conceived the ideas and designed methods; NSG, TJH, and MGT collected, analyzed, and interpreted the data; and NSG led the writing of the manuscript, to which all authors contributed critically and gave approval for publication.
Publisher Copyright:
© 2020 by the Ecological Society of America
PY - 2020/9/10
Y1 - 2020/9/10
N2 - Subalpine forests that historically burned every 100–300 yr are expected to burn more frequently as climate warms, perhaps before trees reach reproductive maturity or produce a serotinous seedbank. Tree regeneration after short-interval (<30-yr) high-severity fire will increasingly rely on seed dispersal from unburned trees, but how dispersal varies with age and structure of surrounding forest is poorly understood. We studied wind dispersal of three conifers (Picea engelmannii, Abies lasiocarpa, and Pinus contorta var. latifolia, which can be serotinous and nonserotinous) after a stand-replacing fire that burned young (≤30 yr) and older (>100 yr) P. contorta forest in Grand Teton National Park (Wyoming, USA). We asked how propagule pressure varied with time since last fire, how seed delivery into burned forest varied with age and structure of live forest edges, what variables explained seed delivery into burned forest, and how spatial patterns of delivery across the burned area could vary with alternate patterns of surrounding live forest age. Seeds were collected in traps along 100-m transects (n = 18) extending from live forest edges of varying age (18, 30, and >100 yr) into areas of recent (2-yr) high-severity fire, and along transects in live forests to measure propagule pressure. Propagule pressure was low in 18-yr-old stands (~8 seeds/m2) and similarly greater in 30- and 100-yr-old stands (~32 seeds/m2). Mean dispersal distance was lowest from 18-yr-old edges and greatest from >100-yr-old edges. Seed delivery into burned forest declined with increasing distance and increased with height of trees at live forest edges, and was consistently higher for P. contorta than for other conifers. Empirical dispersal kernels revealed that seed delivery from 18-yr-old edges was very low (≤2.4 seeds/m2) and concentrated within 10 m of the live edge, whereas seed delivery from >100-yr-old edges was >4.9 seeds/m2 out to 80 m. When extrapolated throughout the burned landscape, estimated seed delivery was low (<49,400 seeds/ha) in >70% of areas that burned in short-interval fire (<30 yr). As fire frequency increases, immaturity risk will be compounded in short-interval fires because seed dispersal from surrounding young trees is limited.
AB - Subalpine forests that historically burned every 100–300 yr are expected to burn more frequently as climate warms, perhaps before trees reach reproductive maturity or produce a serotinous seedbank. Tree regeneration after short-interval (<30-yr) high-severity fire will increasingly rely on seed dispersal from unburned trees, but how dispersal varies with age and structure of surrounding forest is poorly understood. We studied wind dispersal of three conifers (Picea engelmannii, Abies lasiocarpa, and Pinus contorta var. latifolia, which can be serotinous and nonserotinous) after a stand-replacing fire that burned young (≤30 yr) and older (>100 yr) P. contorta forest in Grand Teton National Park (Wyoming, USA). We asked how propagule pressure varied with time since last fire, how seed delivery into burned forest varied with age and structure of live forest edges, what variables explained seed delivery into burned forest, and how spatial patterns of delivery across the burned area could vary with alternate patterns of surrounding live forest age. Seeds were collected in traps along 100-m transects (n = 18) extending from live forest edges of varying age (18, 30, and >100 yr) into areas of recent (2-yr) high-severity fire, and along transects in live forests to measure propagule pressure. Propagule pressure was low in 18-yr-old stands (~8 seeds/m2) and similarly greater in 30- and 100-yr-old stands (~32 seeds/m2). Mean dispersal distance was lowest from 18-yr-old edges and greatest from >100-yr-old edges. Seed delivery into burned forest declined with increasing distance and increased with height of trees at live forest edges, and was consistently higher for P. contorta than for other conifers. Empirical dispersal kernels revealed that seed delivery from 18-yr-old edges was very low (≤2.4 seeds/m2) and concentrated within 10 m of the live edge, whereas seed delivery from >100-yr-old edges was >4.9 seeds/m2 out to 80 m. When extrapolated throughout the burned landscape, estimated seed delivery was low (<49,400 seeds/ha) in >70% of areas that burned in short-interval fire (<30 yr). As fire frequency increases, immaturity risk will be compounded in short-interval fires because seed dispersal from surrounding young trees is limited.
U2 - 10.1002/ecy.3194
DO - 10.1002/ecy.3194
M3 - Article
JO - Ecology
JF - Ecology
ER -