Ecology and evolution of pine life histories

Abstract

Introduction Pinus is a diverse genus of trees widely distributed throughout the Northern Hemisphere. Understanding pine life history is critical to both conservation and fire management. Objectives Here I lay out the different pathways of pine life history adaptation and a brief overview of pine evolution and the very significant role that fire has played. Results Pinus originated ~150 Ma in the mid-Mesozoic Era and radiated across the northern continent of Laurasia during the Cretaceous Period. Pines have followed two evolutionary strategies interpreted as responses to competition by the newly emerging angiosperms. The Strobus lineage mostly has radiated into stressful sites of low nutrient soils and extremes in cold or heat. The Pinus (subgenus) lineage has radiated into fire-prone landscapes with diverse fire regimes. Examination of life history traits illustrates syndromes associated with fire-avoider, fire-tolerater, fire-embracer, and fire-refuge strategies. Conclusion Understanding the current pattern of pine distribution requires interpreting their evolution in terms of climate, geology, and fire. All three of these factors have played a role since the Mesozoic origin of the genus. All are important to the appropriate management of these resources.

Fire intensity impacts on post-fire temperate coniferous forest net primary productivity

“…Numerous studies have linked morphological traits to post-fire survival; thicker bark, deep rooting depth, and a high, open tree crown have all been identified as characteristics that increase relative fire resistance of a tree (Fischer and Bradley, 1987;Harrington, 2013;He et al, 2012;Keeley, 2012;Midgley et al, 2011;Ryan and Reinhardt, 1988;Starker, 20 1934;VanderWeide and Hartnett, 2011). However, many studies assume a binary response regarding fire impacts on vegetation: either mortality (immediate or delayed) or no physiological effect .…”

Understanding long-term post-fire regeneration of a fire-resistant pine species

“…Although seedling density fluctuates during the year, the continuous supply of seeds and seasonal turnover allows the existence of a permanent seedling bank, which ensures stable, mature populations of P. canariensis. The regeneration dynamic pattern shown by P. canariensis combines a mixture of fire tolerant and fire embracer Mediterranean pine regeneration strategies (Keeley 2012).…”

“…Pine strategies to cope with fire depend on either species persistence (by sexual reproduction) or individual survival (Keeley 2012). Obligate seeders, like Pinus halepensis Mill., survive due to serotinous cones that store seeds in aerial banks and then release them only or mostly after fire, producing an immediate post-fire seedling cohort, whose recruitment gives rise to a new population (Keeley 2012).…”

“…Pine strategies to cope with fire depend on either species persistence (by sexual reproduction) or individual survival (Keeley 2012). Obligate seeders, like Pinus halepensis Mill., survive due to serotinous cones that store seeds in aerial banks and then release them only or mostly after fire, producing an immediate post-fire seedling cohort, whose recruitment gives rise to a new population (Keeley 2012). Species without serotinous cones living in fire-prone environments, such as Pinus nigra Arnold or Pinus pinea L., have very scarce regeneration after fires and depend exclusively on the ability of reproductive adults to survive and generate subsequent cohorts.…”

Pine Plantations and Invasion Alter Fuel Structure and Potential Fire Behavior in a Patagonian Forest-Steppe Ecotone

“…For example, in northwestern Patagonia, Argentina, pines have been planted along the forest-steppe ecotone since the late 1970s [13] and escaped pines from plantations have rapidly become biological invaders in several formerly treeless areas [14]. In this region, the most commonly planted species is Pinus ponderosa Douglas ex C. Lawson and the most widespread invasive pine species is Pinus contorta Douglas, both of which experience frequent fire in their native environments and thus have life-history traits that generally make them well adapted to fire [15]. Furthermore, both species have fast growth rates and thus rapid fuel load accumulation, particularly in the introduced range [16,17].…”