Journal of Geography  & Natural Disasters
Open Access

Abstract

Topographic Relief, Wind Direction, and Conservation Management Decisions Influence Cycas micronesica K.D. Hill Population Damage during Tropical Cyclone

Thomas E Marler, John H Lawrence and Gil N Cruz

Typhoon Dolphin damaged forest resources in northern Guam on 15 May 2015, and we assessed the responses of the native tree Cycas micronesica to the destructive winds. We compared the damage to that of previous typhoons, evaluated topographic traits that affected tree damage, and assessed the influence of prior management decisions for in situ conservation plots on damage. Snapping of stems near the ground was greater in this typhoon than in past typhoons, confirming predictions that chronic infestations of non-native insect herbivores compromised the biomechanical integrity of stem tissue. Tree failure as snapping of stems or uprooting/toppling increased from 1% to 23% along an elevation gradient that faced windward, indicating orographic lifting increased wind force and mediated the tree response. Two years of conservation management within in situ plots reduced tree damage and saved up to 16% of the population, depending on site. Case studies such as this one are needed to more fully understand future impacts of increased frequency of intense TCs that are predicted with climate change models.