YELA Forest Literature

Lessons From the Pacific Islands – Adapting to Climate Change by Supporting Social and Ecological Resilience. Mcleod et al, Frontiers in Marine Science, 2019.

By necessity, Pacific Islands have become hubs of innovation, where climate strategies are piloted and refined to inform adaptation efforts globally. Pacific Island ecosystems are being degraded by pollution, overfishing, and unsustainable development. They also increasingly face severe climate impacts including sea-level rise, changing temperature and rainfall patterns. These impacts result inchanges in food and water security, loss of identity, climate-induced migration and threats to sovereignty. In response, communities in the region are leading climate adaptation strategies, often combining traditional practices and cutting-edge science, to build the resilience of their communities and ecosystems in the face of increasing climate risk. For example, communities are implementing resilient networks of marine protected areas using the best available science and strengthening tribal governance to manage these networks, experimenting with salt and drought tolerant crops, revegetating coastlines with native salt-tolerant plants, revitalizing traditional wells, and implementing climate-smart development plans. Often these efforts contribute to local development priorities and create co-benefits for multiple sustainable development goals (SDGs). These community efforts are being scaled up through provincial and national policies that reinforce the critical role that ecosystems play in climate adaptation and provide a model for the rest of the world. While adaptation efforts are critical to help communities cope with climate impacts, in some cases, they will be insufficient to address the magnitude of climate impacts and local development needs. Thus, there are inherent trade-offs and limitations to climate adaptation with migration being the last resort for some island communities.

Keywords: small island developing states (SIDS), climate change, Pacific Islands, vulnerability, adaptation, ecosystem-based adaptation

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Surface Elevation Change and Susceptibility of Different Mangrove Zones to Sea-Level Rise on Pacific High Islands of Micronesia. Krauss et al, Ecosystems, 2010

Mangroves on Pacific high islands offer a number of important ecosystem services to both natural eco- logical communities and human societies. High is- lands are subjected to constant erosion over geologic time, which establishes an important source of ter- rigeneous sediment for nearby marine communities. Many of these sediments are deposited in mangrove forests and offer mangroves a potentially important means for adjusting surface elevation with rising sea level. In this study, we investigated sedimentation and elevation dynamics of mangrove forests in three hydrogeomorphic settings on the islands of Kosrae and Pohnpei, Federated States of Micronesia (FSM). Surface accretion rates ranged from 2.9 to 20.8 mm y-1, and are high for naturally occurring mangroves. Although mangrove forests in Micro- nesian high islands appear to have a strong capacity to offset elevation losses by way of sedimentation, elevation change over 61⁄2 years ranged from -3.2 to 4.1 mm y-1, depending on the location. Mangrove surface elevation change also varied by hydrogeo- morphic setting and river, and suggested differential, and not uniformly bleak, susceptibilities among Pa- cific high island mangroves to sea-level rise. Fringe, riverine, and interior settings registered eleva- tion changes of -1.30, 0.46, and 1.56 mm y-1, respectively, with the greatest elevation deficit (-3.2 mm y-1) from a fringe zone on Pohnpei and the highest rate of elevation gain (4.1 mm y-1) from an interior zone on Kosrae. Relative to sea-level rise estimates for FSM (0.8–1.8 mm y-1) and assuming a consistent linear trend in these estimates, soil ele- vations in mangroves on Kosrae and Pohnpei are experiencing between an annual deficit of 4.95 mm and an annual surplus of 3.28 mm. Although natu- ral disturbances are important in mediating eleva- tion gain in some situations, constant allochthonous sediment deposition probably matters most on these Pacific high islands, and is especially helpful in cer- tain hydrogeomorphic zones. Fringe mangrove for- ests are most susceptible to sea-level rise, such that protection of these outer zones from anthropogenic disturbances (for example, harvesting) may slow the rate at which these zones convert to open water.

Key words: disturbance; hydrogeomorphic zone; sea-level rise; subsidence; surface-elevation table; vertical accretion; wetlands; Federated States of Micronesia.


A tropical freshwater wetland: I. Structure, growth, and regeneration. Allen et al, Wetlands Ecology and Management, 2005

Forested wetlands dominated by Terminalia carolinensis are endemic to Micronesia but common only on the island of Kosrae, Federated States of Micronesia. On Kosrae, these forests occur on Nansepsep, Inkosr, and Sonahnpil soil types, which differ in degree of flooding and soil saturation. We compared forest structure, growth, nutrition, and regeneration on two sites each on Nansepsep and Inkosr soils and one site on the much less common Sonahnpil soil type. Terminalia tree sizes were similar on all three soil types, but forests differed in total basal area, species of smaller trees, and total plant species diversity. Terminalia regeneration was found only on the Inkosr soil type, which had the highest water table levels. Other Terminalia species are relatively light demanding, and T. carolinensis exhibited similar characteristics. It is therefore likely that Terminalia requires periodic, but perhaps naturally rare, stand-replacing disturbances (e.g., typhoons) in order to maintain its dominance, except on the wettest sites, where competition from other species is reduced. Terminalia swamps in the Nansepsep soil type appeared to be at the greatest risk of conversion to other uses, but swamps on all three types may face greater pressure as Kosrae’s population increases and the island’s infrastructure becomes more developed.

Key words: Coarse woody debris, Dendrometry, Disturbance, Endemism, Fertility, Horsfieldia nunu, Kosrae, Micronesia, Soils, Species diversity, Terminalia carolinensis.


A tropical freshwater wetland: II. Production, decomposition, and peat formation. Chimner et al, Wetlands Ecology and Management, 2005

As much as 10% of the total carbon stored in peatlands occurs in the tropics. Although tropical peatlands are poorly understood scientifically, they are increasingly exploited for a variety of human uses. Our objective was to measure baseline carbon cycling data in one type of tropical peatland in order to understand better how peat accumulates in these ecosystems. Average plant production for two study sites on the island of Kosrae in the Federated States of Micronesia over 2 year was 1122 g C m2 year1, of which 1058 g C m2 year1 was aboveground plant production (bole, buttress and litterfall). Although leaves contributed a high proportion of total plant productivity, their rapid decomposition left little carbon for peat accumulation. In contrast, fine roots only contributed 10% to plant productivity, but their slow decomposition allowed them to accumulate as peat. Wood (branches and stems) probably contributed the most carbon to the formation of peat. Despite being on the soil surface, small branches decomposed more slowly than leaves because of their high C:N and lignin:N ratios. In summary, we suggest that tropical peatlands in Micronesia accumulate peat not because of high plant production but rather because of slow decomposition of roots and wood under anaerobic conditions that result from nearly constant high water levels.

Key words: Carbon cycling, Decomposition, Kosrae, Micronesia, Peatlands, Plant production.


A tropical freshwater wetland: III. Direct use values and other goods and services. Drew et al, Wetlands Ecology and Management, 2005

Understanding the economic value of a wetland as well as how people perceive its role in providing goods and services can provide insight into the wetland’s actual role and the kinds of policies needed to ensure sustainable use. On the island of Kosrae, Federated States of Micronesia, freshwater forested wetlands dominated by Terminalia carolinensis (hereafter called Terminalia) are often found just upslope from mangrove forests, which appear to be hydrologically connected to them. Many of these Terminalia forests have been converted into agroforests. A survey of 10% of the households on Kosrae showed that 89% owned some Terminalia land. Most grew taro, bananas, and sugar cane, either in or immediately adjacent to Terminalia forests. Most owned canoes constructed of Terminalia logs, and nearly half had harvested trees from these forests during the past year: 64% to clear land for agricultural purposes, 36% for building canoes, and 31% for other uses. Terminalia forests provided over $3.1 million worth of goods to Kosra- eans, primarily from agricultural production. Approximately 2/3 of those surveyed understood that Ter- minalia grows best in a wetland setting. Most thought that Terminalia forests provide erosion protection and improve water quality. However, very few were cognizant of the ecological links between Terminalia and mangrove forests. Kosraeans attached little importance to the fact that Terminalia is endemic to the eastern Caroline Islands. If human dependence on these wetlands increases, the integrity of Terminalia forests, as well as adjacent mangrove forests, could be at risk.

Key words: Agroforestry, Ecosystem services, Endemic species, Kosrae, Micronesia, Terminalia carolinensis, Wetland valuation.


Botanical Survey of the Yela River Valley, Kosrae, F.S.M., Final report to the Intitute of Pacific Islands Forestry, Lorence et al, 2005

Microsoft Word – Yela survey.doc

A botanical survey of the Yela River valley in western Kosrae, F.S.M. was conducted to characterize the vegetation types (plant communities) in the area and determine their vascular plant species composition. The flora was documented by means of herbarium specimens, field identifications, and digital photos. Four vegetation types were recognized for the valley: (1) a well-developed fringing coastal mangrove forest occurs at sea level; (2) a majestic Terminalia-Horsfieldia swamp forest covers the valley bottom, extending to ca. 40-50 m elevation; (3) a lowland, non-swamp wet forest replaces it at elevations above ca. 20-30 m; (4) lower montane wet forest covers the rock outcrops, slopes, and ridges of the flanking mountains beginning at ca. 5 m . Ninety-nine vascular plant species and infra-species were recorded. Of these, 77 (77.8%) are indigenous, 13 (13.2%) are naturalized, 5 (5.2%) are endemic, and 4 (4.0%) are cultivated. The area supports a healthy, thriving forest with little disturbance, abundant seed production, numerous seedlings of all age groups, and very few naturalized plants, whose impact is minimal. This drainage area is a critical watershed for northwestern Kosrae. Its intact forest cover prevents erosion and damage to the coral reefs, while the mangroves buffer the coast and provide protection for juvenile marine organisms. The This truly unique ecosystem serves as a valuable watershed that help protect the reef from siltation, serves as a reservoir for biodiversity on the island,

KEY WORDS: Kosrae, Federated States of Micronesia, botanical survey, vascular plants, mangrove forest, swamp forest, lowland, lower montane, wet forest

A Pristine Tropical Landscape: Yela Valley, Kosrae, Federated States of Micronesia, Ewel et al, Institute of Pacific Islands Forestry

The freshwater forested wetland in the Yela Valley of Kosrae, Federated States of Micronesia, is the heart of an unusually pristine tropical watershed extending from ridgetop to reef. It contains the largest remaining stand of Terminalia carolinensis (locally known as ka) in the world. The immense buttresses of the ka support canoe-log boles and multi-layered canopies. In addition to ka, which is endemic to Kosrae and the neighboring island of Pohnpei, this wetland contains several other endemic plant species, and it provides habitat for the Micronesian pigeon, an endangered species. Currently inaccessible by road, the Yela Valley is the largest and perhaps the most valuable intact landscape remaining in Kosrae, despite the high value of its timber. 

Climate Change in the Federated States of Micronesia: Indicators and Considerations for Key Sectors, Grecni et al, 2023

Climate Change in the Federated States of Micronesia: Indicators and Considerations for Key Sectors is a report developed by the Pacific Islands Regional Climate Assessment (PIRCA).
It is one in a series of reports aimed at assessing the state of knowledge about climate change indicators, impacts, and adaptive capacity of the US-Affiliated Pacific Islands (USAPI) and the Hawaiian archipelago. PIRCA is a collaborative effort engaging federal, state, and local government agencies, non-governmental organizations, academia, businesses, and community groups to inform and prioritize their activities in the face of a changing climate.

The initial phase of PIRCA activities was conducted during June–October 2019 and included meetings and workshops in American Sāmoa, the Republic of Palau, the Commonwealth of the Northern Mariana Islands (CNMI), and Guam. The draft PIRCA report for the Federated States of Micronesia (FSM) was developed and refined through virtual engagement with experts from the PIRCA network in April 2022– March 2023. The material presented in this report
is based largely on published research and insights from participants in PIRCA activities. Workshop participants and reviewers independent of the PIRCA workshops who made contributions are recognized as Technical Contributors.