76 
D. R. MELICK 
the correlation of relatively alkaline soils with 
significantly higher exchangeable calcium levels 
(Table 4). Such soils are found along the lower 
section ofWoolshed Creek, the northern plateau 
and seepage areas above the Mitchell River. 
The values of acid (Bray-Kurtz) extractable 
phosphorus are likely to reflect not only the par¬ 
ent material and weathering processes, but also 
the degree and quality of litter cycling (Attiwill & 
Leeper 1987). The acid extractable phosphorus 
contents of the majority of soils in the area lay 
between 10 and 60 ppm. these being average 
levels for Australian soils (Beadle 1954, 1962). 
However, large areas of soils with low phospho¬ 
rus levels (<20 ppm) occur on the plateaux 
under dry sclerophyll forest in the southern and 
northern parts of the park. Isolated pockets of 
soils with higher levels of phosphorus (60-170 
ppm) occur along Woolshed and Bull Creeks. 
High phosphorus levels do not appear to have 
any consistent correlation with other soil prop¬ 
erties (Table 4) but are probably due to increased 
nutrient cycling from the rainforest and from 
wet vegetation, as well as to the movement of 
soil and debris down the slopes of the gullies. 
However, the sand deposits in the creek beds 
under rainforest are very nutrient-poor, with 
available phosphorus levels of less than 10 ppm. 
Although sandy soils under the rainforest are 
very low in extractable phosphorus, the rate of 
release of nutrients from litter fall may be more 
significant than a static value at any one time. 
Description of vegetation 
From the numerical analyses of floristic data 
three supergroups, each representing commu¬ 
nity types, were delineated: A (rainforest com¬ 
munities), B (damp sclerophyll communities), 
and C (dry sclerophyll communities). Each of 
the three supergroups include two subordinate 
groups: Al, A2; Bl, B2; and Cl, C2. These 
subordinate groups represent the six community 
types recognized in this study. 
* The dendrogram illustrating the hierarchical 
relationship, and the ordination plot showing 
the relative similarity of the six community 
groups, are shown in Figs 2 and 3 respectively. 
The six major community types recognized are 
described below and their locations within the 
study site are mapped in Fig. 4. The frequencies 
of species within each of these community types 
are listed in Appendix 1. 
Supergroup A. Rainforest communities 
These communities were clearly delineated fior- 
istically in the classification and ordination by 
t t ? f | ! 
<3 (3 c5 o o 6 
Fig. 2. Dendrogram showing the hierarchical classifi¬ 
cation (MACINF) of 260 quadrats above the 6 group 
level of the community types. 
57 quadrats. Supergroup A was divided into two 
groups, one being typical closed forest along 
Woolshed Creek and upper Bull Creek (group 
Al), the other being more open and disturbed as 
a result of the 1965 fire along the lower reaches 
of Bull Creek and the banks of the Mitchell River 
(group A2). 
Undisturbed rainforest (group Al, 27 quadrats). 
A closed canopy (>85% cover) up to 35 m tall 
and composed of Acmena smithii, Pittosporum 
undulatum, Acronychia oblongifolia and Tris¬ 
tan i apsis lamina dominates this community. 
Thin wiry and slender woody lianes (sensu Webb 
1978). such as Morinda jasminoides, Smi/ax 
australis, Eustrepbus latifolius, Marsdenia ros- 
trata and Pandorea pandorana are abundant. A 
sparse understorcy (average 6% cover) of the 
shrubs Olear ia argophylla, O. Ii rat a, Hymenan- 
thera dentata and Coprosma quadrifida is pre¬ 
sent. The rainforest supports a wide variety of 
ferns, including Pellaea falcata, Adiantum 
aethiopicum, Asplenium JlabeUifoUum, Doodia 
aspera, Polystichum proliferum, P. Jbrmosum, 
Microsorium diversifolium and the tree ferns 
Dicksonia antarctica and Cyathea australis. The 
mosses Breutelia qffinis and Thuidium laevius- 
culum are also very prominent in the ground 
stratum, while Weymouthia cochlearifolia is a 
