Implications of tropical cyclones on damage and potential recovery and restoration of logged forests in Vietnam

Abstract

Many natural forests in Southeast Asia are degraded following decades of logging. Restoration of these forests is delayed by ongoing logging and tropical cyclones, but the implications for recovery are largely uncertain. We analysed meteorological, satellite and forest inventory plot data to assess the effect of Typhoon Doksuri, a major tropical cyclone, on the forest landscapes of central Vietnam consisting of natural forests and plantations. We estimated the return period for a cyclone of this intensity to be 40 years. Plantations were almost twice as likely to suffer cyclone damage compared to natural forests. Logged natural forests (9–12 years after cessation of government-licensed logging) were surveyed before and after the storm with 2 years between measurements and remained a small biomass carbon sink (0.1 ± 0.3 Mg C ha −1 yr −1 ) over this period. The cyclone reduced the carbon sink of recovering natural forests by an average of 0.85 Mg C ha −1 yr −1 , less than the carbon loss due to ongoing unlicensed logging. Restoration of forest landscapes in Southeast Asia requires a reduction in unlicensed logging and prevention of further conversion of degraded natural forests to plantations, particularly in landscapes prone to tropical cyclones where natural forests provide a resilient carbon sink. This article is part of the theme issue ‘Understanding forest landscape restoration: reinforcing scientific foundations for the UN Decade on Ecosystem Restoration’.

Global vulnerability and resilience of coastal ecosystems to tropical cyclones in a warming climate

“…Contrasting with many local assessments [21,26] associated with specific events [25], here we derived potential vulnerability relationships between the large-scale natural hazards of tropical cyclones, and ecosystems at a global scale. We used our approach inspired by the panarchy principles [52,60] and based on the frequency patterns of the storms to characterize ecosystem vulnerability under present climate conditions.…”

“…Tropical cyclones have been shown to impact ecosystems through various processes such as wind throw, causing defoliation and canopy damage, which can lead to reduced photosynthesis, growth, and productivity of trees, as well as increased susceptibility to pest and disease outbreaks [16,18]. Heavy rain can cause landslides, soil erosion, and nutrient loss [19] potentially causing decreased growth and productivity of vegetation, but also direct vegetation mortality [20], especially when already disturbed by anthropogenic land use [21]. Storms can add large amounts of saltwater to coastal freshwater and terrestrial ecosystems disrupting habitats [22].…”

Fifteen essential science advances needed for effective restoration of the world's forest landscapes

“…Therefore, more work is needed to understand the relative importance of the multiple drivers of restoration success, and how they interact. In this theme issue, wind damage in Vietnam is shown to be more detrimental to forest recovery where past disturbance and land-use change have been greatest [ 68 ], while planted seedling survival across Southeast Asian sites was highly variable, but particularly connected to habitat condition at time of planting [ 69 ]. Similarly, new data in the theme issue from Brazil show an increase in forest restoration success with soil quality and proximity to forests [ 70 ].…”

“…Alongside immediate impacts, disturbance of all kinds may lead to further feedbacks that affect forest functioning (Advance 15). Implications of disturbance for forest landscape recovery remain largely uncertain [ 68 ] but where disturbance is excessive, e.g. heavy logging, it can lead to degradation and hence arrested recovery and loss of core ecosystem attributes and functions [ 81 ].…”

“…In this theme issue, new research from Brazil shows that alternative restoration approaches are needed according to the level of disturbance [ 70 ]. The theme issue also reveals that forest plantations in Vietnam are more vulnerable to disturbance than natural forests [ 68 ]. And lessons learned from Australia and Tanzania show that forest restoration under globally increasing fire risk requires better scientific understanding of natural fire regimes and pre-fire conditions [ 83 ] and that local fire risk is crucial to consider in planning for restoration management costs [ 32 ].…”