Browsing by Subject "sugar maple"

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    Climate and competition affect growth and survival of transplanted sugar maple seedlings along a 1700‐km gradient
    (Wiley, 2017) Putnam, Rachel C
    Plant species distributions, broadly shaped by climate, may also be constrained by other species. The degree to which biotic factors affect range limits is unclear, however, and few experimental studies have investigated both biotic and abiotic factors across and beyond a species’ range. We examined seedling survival and net growth for three years in contrasting canopy type (closed canopy vs. gap) and neighbor density (clipped vs. unclipped) environments for northern, central, and southern populations of sugar maple (Acer saccharum) representing a climate- of- origin gradient, experimentally planted from Arkansas, USA to Ontario, Canada at ten forested sites along a 1700- km transect spanning beyond the species’ range. We hypoth-esized that each population’s highest survival and growth would occur in its region of origin, with poorer performance in cooler or warmer areas. Refuting this hypothesis, seedlings of all three populations had greater growth and survival in sites increasingly warmer than their point of origin, although they did show poorer growth and survival at increasingly colder sites. We also hypothesized that maple survival and net growth near and beyond range margins are con-strained primarily by cold temperature limitation in the north, where we expected neighbors to facilitate survival, and by competition in the south, where we expected to enhance survival and growth by reducing neighbor density. Results partially supported the hypothesis concerning biotic interactions: in canopy gaps, understory neighbors enhanced maple growth at the cool-est sites but did not suppress growth as expected at the warmest sites. As the northern popula-tion grew and survived reasonably well beyond the northern range limit, and as all populations performed best at warmer sites, including beyond the southern range limit, there was tepid, if any, support for the hypothesis that climate regulated the northern limit and absolutely no support for the hypothesis that competition regulated the southern limit. Together, these three- year findings with juvenile trees suggest that sugar maple range limits may instead be con-strained by factors besides climate and competition, by those factors at another life stage, and/or by climate events such as heat waves, droughts, and cold snaps that occur at longer return intervals.
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    Minnesota Shade Tree Advocate newsletter, volume 7, issue 4, fall 2005
    (2005) Minnesota Shade Tree Advisory Committee
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    Sugar maple (Acer saccharum Marsh.) provenances differ with climate of origin in survival, growth, and traits along a climate gradient: implications for the species' distribution under climate change
    (2015-12) Putnam, Rachel
    Plant ranges, broadly constrained by climate, may be further shaped by interspecific interactions and intraspecific variation in growth and traits. Changing climate and species composition in plant communities lends urgency to the need to better define the factors determining species’ distributions. This research seeks to determine the effects of temperature and neighbors on sugar maple (Acer saccharum) seedling survival, growth, biomass allocation, and functional traits, and whether this response varies with populations’ climate of origin. I first examine survival and growth of forest-planted seedlings across a natural climate gradient and beyond range limits to determine whether populations’ climate of origin and contrasting neighbor density and light environments affect performance. I find no evidence of climate or competition limitation beyond range margins for populations grown near their region of origin, but populations differ in survival and net growth in a manner consistent with local adaptation and contrasting growth strategies: the northern population has high survival across sites but lower mass than the southern population, which has low survival and growth facilitated by neighbors at northern sites. I then examine whether patterns of root biomass allocation of these same seedlings is affected by climate of the planting site or each populations’ region of origin. I find higher root mass in southern population seedlings than in similarly sized northern population seedlings, and higher root mass fraction at colder sites in the southern (but not northern) population. Finally, I use growth chambers to examine the effects of temperature and light on growth rate and traits for three climatically distinct populations. Growth rate declines with increasing latitude of origin and is lower in the temperature treatment corresponding to the climate of origin for the southern population. High-latitude populations have low SLA and LMF, but populations do not differ in photosynthetic rates. In conclusion, I find potentially adaptive differences in populations’ growth, survival, and plant traits but no direct evidence of climate or competition limitation across the range. This study highlights intraspecific variation in growth and traits, its relevance at range limits, and the need to identify whether reproductive or phenological traits also vary within species.