CFE agenda 100917 - Laserfiche WebLink

Browse Search

more hot spells, more drought, and more intense storms. We don't know the effect on rainfall and fog. Much of the climate in this zone is orographically determined, and may not follow the same patterns as the general regional climate, but this is less so than in the spruce -fir zone. Climatic effects will still be more drastic if fog and orographic clouds become less frequent, while these might mitigate the effect of temperature changes if they persist. Drought may lead to increased potential for wild fire. Northern hardwood forests are not very flammable under the current climate, but could become so in more severe droughts. Drought may eliminate seepage, which is important in some boulder fields. Predicted Ecosystem Reponses: Ecosystem Change: Likelihood: Effect: Magnitude: Comments: Increased Fragmentation Med Neg Med Elevation change Med Neg Med Acreage Change High Neg Med Heat or drought stress could lead to mortality of species, including canopy trees. Deeper soils and greater tolerance of plants makes this less likely than in spruce -fir forests, but it is still a threat in these mesophytic communities. Invasion by species from lower elevations could lead to competitive exclusion of northern hardwood species. However, the canopy species are highly competitive and could hold their own for many years. Under current fire -free conditions, shade - tolerant northern hardwood forest species invade drier oak forests, suggesting they can tolerate drier conditions than currently prevail in these communities. Changes might be slow, resulting from changed reproductive rates, or could be fast if wind or fire destroyed existing canopy. Typic northern hardwood forests may be able to migrate to higher elevation without much change in community composition. Boulder fields can't migrate, and beech gaps may or may not be able to. Increased wind storm damage might favor some trees species over others, but this is likely to be minor. All characteristic trees have the ability to sprout and all are shade - tolerant enough to exist as advance regeneration. Fire would likely be harmful to northern hardwood forests, but may not be catastrophic. Hardwood litter and forb- dominated herb layers carry fire poorly. All major plant species can sprout if burned. However, severe fire could kill old trees. Frequent fire would promote the transition to oak forest. If fire became more common, the current topographic relationship of high elevation red oak forest on dry slope aspects and northern hardwood forest on moist might be altered. This could potentially reduce northern hardwood forests more than elevational shifts alone would predict. 176 Appendix B