LTERN Data Portal

Prof Joseph H. Connell (University of California, Santa Barbara) established a long-term forest dynamics plot in 1963, in tropical rainforest at in Dinden National Park, 25 km south west of Cairns. The plot is 1.7 hectare, and was established over an existing an existing 0.4 ha plot established by the Queensland Department of Forestry in 1951. This plot has never been logged.

Although a summary of methods employed in the study has been provided below, the reader should refer to a comprehensive description of the methods and the plot configuration provided in the Conceptual Design (p 84) and accompanying documentation.

In summary, samples of trees in three broad size classes have been monitored on the plots over several decades. ‘Large trees’ (≥ 10.0 cm dbh) were first tagged, mapped and measured in 1963 across both plots. At the same time, ‘medium trees’ (2.5 cm dbh but < 10.0 cm dbh) were mapped and tagged along several belt transects 6.1 m wide running through the plot, centred on survey lines 20.1 m apart. The medium-tree belt transects comprise 30% of each plot. In 1965, ‘small trees’ (tiny seedlings to saplings < 2.5 cm dbh), were mapped and tagged along narrower transects either 1.8 or 3.6 m wide, centred on the same survey lines used to sample medium trees. Large trees rooted outside the plot boundaries, but whose canopies extended over the plots have also been monitored.

Large and medium trees are tagged with numbered aluminium tree tags inscribed with a unique number, nailed into the trunk with galvanized nails. Small trees are also tagged with numbered aluminium tags, attached to the plant using loops of insulated copper wire. The plots are laid out and trees are mapped using imperial and engineering units (feet and tenths of feet). Large and medium trees are measured for girth at breast height using inches and tenths of inches, and small trees are measured for height in feet and tenths of feet. These are converted to SI Units for analyses and publication. The belt transects comprise 30% of each plot. The seedlings of vines are occasionally tagged by inexperienced workers, but these are excluded from analyses.

Further details relating to the methods employed by the Connell Rainforest Plot Network during this study can be found on the LTERN Plot Network site.

Gaps created by the death of large canopy trees have been systematically surveyed many times over the decades until 2002, with the boundaries of the gaps being noted on hand drawn maps. These maps have never been digitized, and the originals are held at the University of California. Copies of some later maps are held by Peter Green at La Trobe University.

Voucher specimens have been collected on an ad hoc basis over the years for many individuals on the plot. These specimens are subject to curation at La Trobe University. Species lists are updated as taxonomic changes are published. Major taxonomic revisions of the rainforest Myrtaceae and Lauraceae pose some problems for analyses. These revisions have erected many new species and changed old ones, and of course it is impossible to apply the revised taxonomy to unvouchered specimens (i.e. dead stems).

Stand structure, canopy cover and variation in understorey light environments have not been measured systematically on the plots. Under LTERN, new surveys for canopy cover and understorey light environments using hemispherical photography are being incorporated into regular plot monitoring.