Botanical Overview

The following information has been prepared by forest ecologist, Anton Ingarfield.
Mt Hyland Nature Reserve contains two forest formations consisting of

Open Forests Communities of

Mt. Hyland Nature Reserve

 

A.    Mid-altitudes at 800 to 1100m ASL

Tall Wet Sclerophyll Forest

    •  Forest Type #46; Sydney Blue Gum
      On the highest fertility sites at around 950m ASL to the south of the Lodge, on soils derived from a basalt capping a tall, moist eucalypt forest of almost pure Sydney Blue Gum with occasional Brush Box occurs. The trees are mostly regrowth from sapling to spar size with a few mature trees. There are also a few rainforest trees such as Crabapple, Soft Corkwood and Hoop Pine and a well-developed mesophytic understorey of rainforest shrubs, small trees and vines. There may have been a small semi-natural grassland plain similar to Chapmans Plain and other Dorrigo grassland plains on top of the wide knoll associated with the basalt capping. Severe cold and periodic burning may have perpetuated this grassland plain in the past. The Sydney Blue Gum represents a cold hardy pioneer for the regenerating rainforest. In the absence of fire and other disturbance over a long period (>200 years) this forest may develop into a Cool Subtropical Rainforest of Sub-alliance #12 with mature Sydney Blue Gum and Brush Box emergents.
    •  Forest Type #47; Tallowwood-Sydney Blue Gum
      In sheltered and moderately fertile (may be due to basalt enrichment) sites that have been free of fire for many years, a tall (up to 55m), moist eucalypt forest (Wet Sclerophyll Forest) dominated by Tallowwood and Sydney Blue Gum occurs. Associated trees include Brush Box, Turpentine, Silvertop Stringybark and New England Blackbutt. As above there is a well-developed small tree and shrub layer of rainforest species. In the absence of fire and other disturbance over a long period (>200 years) this forest may develop into a Cool Subtropical Rainforest of Sub-alliance #12 or possibly an Intermediate Cool Subtropical / Warm Temperate Rainforest of Sub-alliance #33 with mature Tallowwood, Sydney Blue Gum and Brush Box emergents.

 

    •  Forest Type #163; New England Blackbutt-Tallowwood
      In somewhat less fertile but still relatively moist sites with infrequent fire a tall (up to 55m) wet sclerophyll forest occurs but with a change in dominant species. Sydney Blue Gum, although present, becomes less frequent to be replaced by New England Blackbutt as the main associate of Tallowwood. Other associates are Messmate and Silvertop Stringybarks, Brown Barrel and Manna Gum. This forest type has a more or less mesophytic (rainforest) understorey depending on fire frequency. In the absence of fire and other disturbance over a long period these forests may develop into a Warm Temperate Rainforest of Sub-alliance #36 with Tallowwood and New England Blackbutt emergents.

 

    •  Forest Type #160; New England Blackbutt-Diehard Stringybark
      On sites of low to moderate fertility, but moist aspect with infrequent fire, Tallowwood is replaced by Diehard Stringybark in a tall Wet Sclerophyll Forest. The understorey is more or less mesophytic depending on fire frequency. In the absence of fire and other disturbance over a long period these forests may develop into a Warm Temperate Rainforest of Sub-alliance #36 with New England Blackbutt and Diehard Stringybark emergents.

 

Medium/Tall Dry Sclerophyll Forest

    •  Forest Type #163; New England Blackbutt-Tallowwood
      On drier sites with a more northerly or westerly aspects fire becomes more frequent. On sites of moderate to high fertility the same forest type as above may occur but as a medium (less than 25m) to tall (up to 35m) Dry Sclerophyll Forest. The understorey may consist of xerophytic (dry/heath) shrubs or may be grassy depending on the frequency of fire.

 

    •  Forest Type #160; New England Blackbutt-Diehard Stringybark
      On similarly dry aspects but on sites of only low to moderate fertility Tallowwood becomes less frequent to be replaced by Diehard Stringybark as the main associate of New England Blackbutt. Other associates may be Brown Gum, Messmate Stringybark and Manna Gum. This open forest may be either medium (less than 25m) in height or tall (up to 35m). As above, the understorey may consist of xerophytic (dry/heath) shrubs or may be grassy depending on the frequency of fire.

 

 

Aspect/

Fire Frequency

Fertility

Low to Moderate

Moderate

Moderate to High

Moist/

Low to moderate fire frequency

Wet Sclerophyll Forest;

NE Blackbutt-Diehard Stringybark

+/- mesophytic understorey

Wet Sclerophyll Forest;

NE Blackbutt-Tallowwood

+/- mesophytic understorey

Wet Sclerophyll Forest;

Sydney Blue Gum or

Tallowwood-Sydney Blue Gum

+/- mesophytic understorey

Dry/

Moderate to high fire frequency

Dry Sclerophyll Forest;

NE Blackbutt-Diehard Stringybark

+/- xerophytic understorey

Dry Sclerophyll Forest;

NE Blackbutt-Tallowwood

+/- xerophytic understorey

Dry Sclerophyll Forest;

NE Blackbutt-Tallowwood

+/- xerophytic understorey

Forest types on moist to wet sites in relation to fire frequency. Fire free period to climax rainforest, and the type of climax rainforest occurring, is dependent on altitude, aspect, soil depth and fertility and wind exposure.

Fire Frequency

High

Moderate

Low

Very low

Fire free

<10 years

10 to 20 years

20 to 50 years

50 to 200 years

200 to 600-1000 years

>600-1000 years

WSF with Rough Tree Fern, Ground Fern or Grass understorey

WSF with mesophytic understorey

of fire tolerant species only

WSF with mesophytic understorey of both fire tolerant and intolerant species

WSF with well developed rainforest sub-canopy of both fire tolerant and intolerant species

Rainforest with mature and/or senescent sclerophyll emergents

Pure Rainforest

B. High altitudes at 1100-1400m ASL

Tall Wet Sclerophyll Forest

  • Forest Type #152; Messmate-Gum
    On moist sites with low fire frequency at altitudes over 1100m a tall (up to 30m), moist eucalypt forest occurs which is dominated by Messmate in association with New England Blackbutt, Brown Barrel, Giant White Gum and Snow Gum at the highest altitudes. The understorey is more or less mesophytic depending on fire frequency and includes White Banksia. In the absence of fire and other disturbance over long periods this forest may develop into a Warm Temperate Rainforest of Sub-alliance #36 or an Intermediate Cool/Warm Temperate Rainforest of Sub-alliance #40.

Medium Dry Sclerophyll Forest

  • Forest Type #152; Messmate-Gum
    On drier aspects sites at similar altitude the above Forest Type occurs as a medium (less than 25m), dry eucalypt forest again dominated by Messmate but in association with Diehard and Youman’s Stringybark, Narow-leaved and New England Peppermints, Brown Barrel and Mountain Gum. The understorey may consist of xerophytic shrubs or grass depending on the frequency of fire.

Aspect/

Fire Frequency

High Altitude Open Forest

Moist/

Low fire frequency

Wet Sclerophyll Forest;

Messmate Stringybark-Gum

+/- mesophytic understorey

Dry/

Moderate to high fire frequency

Dry Sclerophyll Forest;

Messmate Stringybark-Peppermint-Gum

+/- xerophytic understory

 

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Rainforest Communities of

Mt Hyland Nature Reserve

A. Mid-altitudes at 850 to 1200m

Cool Subtropical Rainforest

  • Soft Corkwood Alliance, Suballiance #12
    At altitudes from 950m to 1100m ASL on argyllite (metamorphic sedimentary) and leuco-adamellite (igneous) in very sheltered sites a Cool Subtropical Rainforest occurs. There may be some localized enrichment from basalt cappings. This rainforest type is “limited to mid-slopes because of exposure to desiccating winds and wildfires up-slope and cold air pockets in the major valley bottoms” (Floyd). The canopy is dominated by Yellow Carabeen, Black Booyong and Giant Stinging Tree. There are occasional Rosewood, Soft Corkwood, Sassafras, Bolly Gum, Red Carabeen and Crabapple. The sub-canopy consists of mostly Brown Beech and Socketwood with the occasional Grey Possumwood, Prickly Ash, Brush Bloodwood and Turnipwood. This is a rich forest with 38 tree species present.

Intermediate Cool Subtropical / Warm Temperate Rainforest;

  • Coachwood Alliance, Suballiance #33
    At altitudes of 850m to 1000m ASL in moderately sheltered sites sub-optimal for the development of pure Cool Subtropical Rainforest an Intermediate Cool Subtropical / Warm Temperate Rainforest occurs. The dominant canopy trees are Yellow Carabeen, Black Booyong and Sassafras with the occasional Mountain Walnut, Crabapple, Rosewood and Purple Cherry. The sub-canopy consists of Coachwood, Prickly Ash and Brown Beech.

Warm Temperate Rainforest;

  • Coachwood Alliance, Suballiance #36 At altitudes of 950m to 1200m ASL in somewhat more exposed sites there is a Warm Temperate Rainforest dominated by Coachwood, Sassafras, Rough Possumwood and with only occasional Yellow Carabeen, Prickly Ash, Soft Corkwood and Crabapple. Here the cold intolerant Coachwood can only survive to higher altitudes where sheltered by the taller Sassafras.

B. High altitudes at 1200 to 1400m

Intermediate Warm Temperate / Cool Temperate Rainforest

  • Sassafras Alliance, Suballiance #40
    At even higher altitudes of 1200m to 1400m on argyllite in relatively sheltered gully heads of Mt. Hyland there occurs an Intermediate Warm Temperate / Cool Temperate Rainforest. The canopy is up to 30 metres high and dominated by Sassafras and Mountain Walnut with the occasional Rough Possumwood and Crabapple. In the sub-canopy Prickly Ash and Mountain Laurel are common with the occasional Mountain Olive-berry, Mountain Marara and Mountain Tree Heath. This is a very interesting rainforest type as a number of the tree species present, as well as some species of fern, are commonly associated with Antarctic Beech elsewhere. Floyd considers that Antarctic Beech probably once occurred here but has died out in past arid periods.

Intermediate Warm Temperate / Cool Temperate Rainforest (Depauperate Form)

  • Sassafras Alliance, Suballiance #40
    On the more exposed ridge spurs and slopes the above rainforest type occurs in a depauperate form type with a low, dense canopy consisting of the wind tolerant small-leaved tree species Sassafras, Mountain Walnut and Mountain Olive-berry. Also common is Mountain Tree Heath and there are few emergent White Banksias, some of which have attained huge proportions.

Warm Temperate Closed Scrub

  • Sassafras Alliance, Suballiance #46
    Warm Temperate Closed Scrub occurs on the steep, very exposed and rocky sites with skeletal soils in the headwaters of Obeloe and Blicks Creeks at altitudes of 1000 to 1400m. Dominating these “scrubs” are Yellow Tea-tree, Veined Mock-olive and Mountain Tree Heath. Other common shrubs are White Banksia, Blackwood and New England Tea-tree. Due to the fact that these “rocky islands” are surrounded by rainforest, and have only a sparse ground layer due to the skeletal soil, they have enjoyed a considerable period of freedom from wildfire. These sites may have been fire free for several hundred years as indicated by the relatively large sized specimens (more than 10 metres) of the normally small tree and shrub species.

Altitude

(metres ASL)

Wind Exposure /

Fertility

Very sheltered /

Moderate to High

Sheltered /

Moderate

Exposed /

Low to Moderate

Very exposed /

Low

850 to

1200

Cool Subtropical Rainforest

Soft Corkwood Alliance

Sub-alliance #12

Intermediate

Cool Subtropical/

Warm Temperate Rainforest

Coachwood Alliance

Sub-alliance #33

Warm Temperate

Rainforest

Coachwood Alliance

Sub-alliance #36

Warm Temperate

Closed Scrub

Sassafras Alliance

Sub-alliance #46

1200 to

1400

None

Intermediate Warm Temperate/ Cool Temperate Rainforest

Sassafras Alliance

Sub-alliance #40

Depauperate Intermediate Warm/Cool Temperate Rainforest

Sub-alliance #40

Warm Temperate

Closed Scrub

Sassafras Alliance

Sub-alliance #46

 

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