National Parks & Wildlife Service Woodland Releves

This dataset is owned and provided by NPWS.

Reccomended reading at; http://www.npws.ie/en/media/NPWS/Publications/Reports/Media,6688,en.pdf

Botanical, Environmental & Conservation Consultants Ltd (2008): National Survey of Native Woodlands 2003-2008 - Volume I (Draft). A report submitted to the National Parks & Wildlife Service

2.3 Relevé survey

A 10 m x 10 m relevé was recorded for each of the vegetation communities identified within surveyed sites. Cover in vertical projection for all vascular and bryophyte species was recorded on the Domin scale (Kent & Coker 1992), as were other general parameters (Appendix 2). The presence of notable lichen species was recorded. For each relevé a 10-figure grid reference was obtained using a GPS and altitude, slope, and aspect were recorded. Soil profiles were examined to a depth of at least 30 cm and classified to Great Soil Group (Gardiner & Radford 1980). Five soil samples were taken from each relevé (one from
the centre and one from each quadrant) with an aluminium soil corer to a depth of 10 cm, and bulked. Soil pH was measured in the field (or immediately on return from the field) using a glass electrode and a 1:1 soil / water paste. Soil samples were then air-dried, crumbled and stored for subsequent laboratory analyses of loss on ignition and total phosphorus. Loss on ignition was determined by heating samples to 500 ºC for 5 hours. To estimate total phosphorus, samples were digested using the Kjeldahl method and phosphorus determined using a molybdenum blue complex by spectrophotometer.
Within each 10 m x 10 m relevé, tree size, abundance and stem quality were measured. The species and number of all stems with a dbh <7 cm were recorded in each relevé using five height classes – a simplified version of Raunkier’s scheme (Raunkier 1934). Differentiation was made between stems which were basal shoots of mature trees and those which were not (free regeneration). As the density of trees varies greatly between woodlands, the plot size for assessment of mature trees (dbh _7 cm) was increased as required beyond the relevé to allow a statistically representative sample of c. 30 trees to be recorded. Each mature stem was given a tree number with multiple stems from the same tree sharing the same tree number. This permitted account to be made for typically multi-stemmed species, such as
hazel, in subsequent density calculations.

For each stem the following information was recorded:
_ Species _ Dbh
_ Crown position relative to other trees was recorded in four classes:
Dominant (trees emerging from the general canopy level)
Co-dominant (trees forming the canopy)
Intermediate (trees in the lower canopy receiving some direct light from above)
Suppressed (trees completely overtopped by the canopy)
_ Height (to the nearest metre)
For trees of minimum merchantable size (dbh >40 cm; Joyce 1998) the following additional data were recorded:
_ Estimated log length – total length, in metres, of the portion of the main stem that was suitable for veneer or sawtimber
_ The presence of the following stem defects: forks, heavy branches, stem galls/cankers, kinks/bends, damaged stem/bark, lean >10%, fluted/buttressed bole, excessive taper, shelf fungi or other stem disease, excessive ivy, epicormic shoots.
Within the relevé, the stratification of the woodland was sketched and photographed and the height and percentage cover for each stratum (canopy, sub-canopy and shrub layer) recorded. All photographs were stored digitally.

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