Coastal Forest Trees Research Articles

Resource allocation and storage relative to resprouting ability in wind disturbed coastal forest trees

Many plants persist by resprouting after disturbance. However, the benefits of resprouting (survival) may be traded off against height growth and reproduction. Resources (total non-structural carbohydrates—TNC) that could be allocated to growth or reproduction are stored or mobilised to support resprouting. TNC may either be stored by accumulation where availability exceeds the requirements for growth, or by reserve formation when storage is at the expense of growth. Thus, the mechanism of storage and resource allocation may differ between good (R+) and poor (R−) resprouters in response to nutrient availability and disturbance regime. R+ species typically reserve resources to ensure a rapid resprouting response to disturbance. We test whether R+ and R− species in coastal forest, under chronic wind disturbance, differ in growth rates, biomass allocation, leaf traits, water relations and storage of TNC. Seedlings from three confamilial pairs of R+ and R− tree species were subjected to nitrogen addition, water stress and clipping (simulating herbivory) treatments under greenhouse conditions. R− species had greater height growth rates, larger specific leaf area, lower root mass ratio and lower root TNC than R+ species. These differences between R+ and R− species were maintained irrespective of the levels of nitrogen, water and clipping treatments. R+ species did not increase their TNC concentration under nutrient and water stress, indicating that TNC is stored by reserve formation. R+ species appeared to trade-off growth against storage, while R− species did not. In R+ species, reserve formation is likely a bet-hedging strategy against occasional strong selection events in addition to chronic wind stress. By trading off height growth for better resprouting ability, good resprouters may be able to persist at more frequently disturbed sites (e.g., dune crests and windward slopes), while poor resprouters that have faster height growth can dominate less disturbed sites.

Vegetation change in the coastal-lowland rainforest at Avai'o'vuna Swamp, Vava'u, Kingdom of Tonga

Avai'o'vuna Swamp, a small coastal wetland in Vava'u, Kingdom of Tonga, produced a 4500-year pollen and sediment record. Results are: (1) a mid-Holocene sea level highstand is confirmed for Tonga between about 4500 and 2600 14C yr B.P.; marine clay contains pollen from mangroves ( Rhizophora mangle), coastal forest trees ( Barringtonia asiatica and Cocos nucifera), and rainforest trees ( Alphitonia, Rhus, Hedycarya and Calophyllum). (2) Microscopic charcoal first appeared at 2600 14C yr B.P., coincident with the arrival of Polynesians. (3) Cocos, Pandanus, Excoecaria, Macaranga, and Elaeocarpaceae pollen reflects the establishment of a mixed coastal-lowland rainforest in the last 2500 years. (4) The loss of Hedycarya, Elaeocarpus, Calophyllum, and Guettarda and the reduction of Terminalia and taxa in the Papilionaceae family by about 1000 years ago may be due to habitat destruction and the loss of dispersal capabilities of some species through the extinction of the two largest pigeons in Tonga.

A METHOD BASED ON THE PIPE MODEL FOR ESTIMATING THE SURFACE AREA AND VOLUME OF COASTAL FOREST TREES, AND THEIR LODGING RESISTANCE

A simplified evaluation method of the surface area and volume of coastal forest trees is proposed by using the Pipe Model based on the physiology of the vegetation. When inundation depth is higher than the tree height, the surface area and volume of tree evaluated by this method were simply determined by the height and diameter of tree. In addition, coastal forest trees' lodging resistance to a reproduced inundated flow by tsunami was investigated. The result of examination was equivalent or smaller than conventional values used for river channels. A quantitative evaluation of coastal forest trees' lodging resistance to tsunami was suggested.

Late Glacial beech forest: an 18,000–5000-BP pollen record from Auckland, New Zealand

Australia, New Zealand and South America are the main sources of terrestrial climate change records for midlatitudes in the Southern Hemisphere. The advantage of studying the New Zealand record is that its vegetation has been subject to human influence for only the last thousand years. Vegetation records for Auckland are important because earlier work indicates that during the Last Glacial Maximum, the boundary between scrubland and forest lay in the Auckland region. Auckland is situated in a volcanic field and the coring site was in the crater of a small extinct volcano (Crater Hill, formed about 29 ka BP). The 4-m long core contained sediment dating from c. 5 to c. 18 ka BP. We present pollen and diatom records from this core. The pollen records from basal clays indicate southern beech forest (mainly Nothofagus menziesii) was present in the region around Crater Hill from 18 to 14.5 ka BP. At this time, there were areas of scrub in the crater surrounding a hardwater lake. The southern forest limit could well have been close to the site. Records from overlying peat indicate beech forest was replaced by Podocarp broadleaf forest as the Last Glacial ended. Metrosideros spp. (coastal forest trees) peak in the early Holocene. This coincides with an impoverished diatom flora which indicates drier conditions in the basin. When the lake reformed in the Holocene on peat its water was more acidic.

Flavonoids of Umbellularia californica

The vacuolar flavonoid profile of Umbellularia californica consists of 3- O-mono-, di- and triglycosides of kaempferol, quercetin and isorhamnetin together with eriodictyol 7- O-glucoside. The leaf exudate contained no flavonoids but did exhibit a small amount of scopoletin. The two growth forms of this species, a shrubby form from dry habitats and a coastal forest tree, exhibited identical flavonoid profiles. These observations were taken to indicate that the flavonoid profile of this species became established before the two growth forms differentiated. The flavonol profile of Umbellularia is consistent with profiles reported for other members of the Lauraceae.

Hurricane Hugo Wind Damage to Southeastern U.S. Coastal Forest Tree Species

One percent of Hobcaw Forest, a 3077 ha tract in South Carolina's lower coastal plain, was inventoried with fixed area plots within four months after the eye of Hurricane Hugo passed 97 km south of the forest. Results of this sampling confirmed our hypotheses that the amount and nature of hurricane wind damage differed among the tree species sampled. Approximately 73 percent of the 16,870 trees inventoried were either not damaged or had light crown damage. Longleaf pine (Pinus palustris) was less damaged than loblolly pine (Pinus taeda) or pond pine (Pinus serotina). Bald cypress (Taxodium distichum) suffered light crown damage. Upland oaks were more heavily damaged than the pine species. Live oak (Quercus virginiana) was less damaged than laurel oak (Quercus laurifolia) and water oak (Quercus nigra). Those tree species commonly found in the lower coastal plain (longleaf pine, bald cypress, and live oak) suffered less damage than species with larger natural ranges.

Coastal Forest Tree Populations in a Changing Environment, Southeastern Long Island, New York

The temporal and spatial dynamics of tree populations in coastal forests of southeastern Long Island, New York, were reconstructed from analyses of (1) historical accounts, maps, and aerial photos, (2) field evidence of forest history (3) age and height class distributions along the moisture gradient, and (4) fossil—pollen content of bordering salt—marsh deposits. Tide—gauge records of sea level provided independent evidence for long—term change in the physical environment (rise in sea level) that caused populations to migrate up the continental shelf. Field evidence for fire and historically documented land—use change demonstrated the important role of disturbance in the dynamics of tree populations. Spatial and temporal patterns in forest, were determined by information on disturbance frequency, dispersal, generation times, and rates of change in the physical environment. Mature cohorts occupied lower elevations than did their progeny because during the period from germination to seed production, suitable soil—moisture conditions shifted upslope in response to sea—level rise. Establishment of new regeneration depended on disturbances that opened the forest canopy and/or prepared seed beds. Frequent fire, land clearance and abandonment, and tree blowdowns insured opportunities for seedling establishment at higher elevations as conditions became unsuitable for regeneration on low—elevation sites. The resultant pattern of range shifts was stepwise, with waves of regeneration following disturbances and subsequent reduced seedling establishment as soil moisture continued to increase. The vegetation dynamics could be explained solely on the basis of life histories of plant species and environmental change; "emergent properties" and "successional stages" in a deterministic sense were not apparent. An understanding of successional change required information on both the spatial and temporal dimensions of vegetation pattern because composition change over time resulted from range shifts in response to environmental transition.

Distribution Patterns and Conservation of Eastern Brazilian Coastal Forest Tree Species

The distributions of 127 tree species, each with at least part of their range in the moist coastal forest of eastern Brazil, are analyzed. Of these, 53.5% are endemic to the coastal forest, 11.8% endemic to the coastal forest plus some part of the Planalto of Brazil, 7.8% disjunct with the Amazonian hylaea, and 26% widespread. This high endemism in the coastal forest of eastern Brazil, in view of its rapid destruction, emphasizes the need for increased preservation of the few remaining natural areas. In addition, this study supports the theory that there are at least two centers of endemism in the coastal forests, one centering around Rio de Janeiro and one in southern Bahia/Rio Doce, Espirito Santo. In order to protect the diverse flora of the coastal forests, preservation areas should be established intermittently along their entire length and especially in the centers of endemism.