Antarctic Beech at Comboyne (Lophozonia moorei)

Photo taken from a paddock in private property. The dark green canopy is unmistakable and easily noticed. Hence the alternative name "Negrohead beech".

 

An unusually low altitude stand of trees at around 600 metres above sea level. Until fairly recently, this Comboyne population was considered "extinct" by scientists. However, the local farmers knew better.

 

The land owner said that this hill had been entirely cleared a hundred years ago, and this is all natural regeneration. The Antarctic Beech is common here. Colin, the local farmer was remarkably friendly, helpful and knowledgeable.

 

The soils here are on colluvium derived from basalt. The rounded conglomerate stones were likely to be from an alluvial origin. Derived from Triassic sediments from around two kilometres upstream. "Colluvium" is loose earth material that has accumulated downhill, through the action of gravity.

 

All sites we visited were basalt influenced, making a reasonably high soil quality. Thanks to Michael for this soil information. At the first site, the tree there was 17 metres tall. It's unlikely any in shot in this photo would exceed 25 metres tall. The largest I've seen of this species is in excess of 50 metres tall at the Barrington Tops.

 

This rainforest may be classified as "warm temperate". As the other trees nearby were almost all of that variety. Such as Native Crabapple, Lilly Pilly, Coachwood, Common Sassafras, White Aspen, Jackwood, Bonewood, Pittosporum, Callicoma, common tree heath, Guioa & Watergum*.

 

* Scientific names; Schizomeria ovata, Acmena smithii, Ceratopetalum apetalum, Doryphora sassafras, Aconychia oblongifolia, Pittosporum undulatum, Callicoma serratifolia, Acradenia euodiiformis, Guioa semiglauca, Tristaniopsis collina.

 

It was interesting to see the Antarctic Beech growing next to Bangalow Palms. As well as more common warmer species such as birds nest ferns. Cool temperate associates include Dicksonia antarctica, Lomatia arborescens, Quintinia sieberi, Orites excelsus and Vesselowskya rubifolia.

 

We noted several Trochocarpa plants, and identified them as the lowland T. laurina, rather than the beech associate, T. montana. Others, however, say that T. montana is present. We searched without success for the Beech orchid. It was recorded in the past at Comboyne, but perhaps now is locally extinct. (Dendrobium falcorostrum).

 

Can't quite figure out why the rainforest is mostly of warm temperate species, as the good quality soils are better suited to sub tropical rainforest trees. Such as the Rosewood, Red Cedar, Pigeonberry Ash, Booyong, Carabeen and dozens and dozens more.

 

At this photographed site, we parked the cars near a grove of original rainforest trees. They were all warm temperate species; (Cryptocarya glaucescens & Doryphora sassafras). Soils were typical red/brown kraznozem types derived from basalt. The streams on the Comboyne plateau are often subject to unusually cold winters, which would assist the Antarctic Beech. Perhaps this rainforest is cool temperate, type 49 as described by Alexander Floyd.

 

Michael E's soil analysis is at odds with Bale & Williams. I reckon Michael is correct, though. My theory is that the Comboyne plateau was covered in warm temperate & sub tropical rainforest. And the warm temperate rainforest is not confined to the Triassic sedimentary soils. (as we saw).

 

I suspected there is an agent in the red/brown kraznozem soils which hinders the development sub tropical species and supports the warm temperate species. It also favours the cool temperate species, the Antarctic Beech. That soil agent may be aluminium or another which renders the soils less fertile in a practical way. (This theory is now discarded).

 

The warm temperate species out-competed the sub tropical types. That missing factor when absent promotes sub tropical rainforest remnants at other farm areas at Comboyne. The sub tropical species out compete the warm temperate species in the richer soils. Temperature, soil degradation after clearing and aspect are factors too. But minor ones, perhaps. I've asked Colin Bale about this, waiting for a reply.

 

The answer is that it's too cold for sub tropical rainforests. The cold air drains down by the creek lines. The rainforest is properly classified as "cool temperate".

 

Although our soils scientist says that the ph is 4 to 5, which could mobilize toxins such as aluminium which could encourage warm temperate species and hinder the growth of sub tropical species.

 

The Comboyne plateau is a scarp-bounded paleoplain located between the central north coast of New South Wales and the Great Escarpment. Location: -31.605, 152.468. Miocene basalts overlie much of the plateau, creating red/brown kraznozem soils. However, exposed in the southern third of the plateau are underlying Triassic sediments of the Lorne basin.

 

The two major streams are the Thone River flowing north and Mumfords Creek, flowing west. The beech trees are found near these streams. The altitudes at the north of the plateau are 450 metres and 700 at the southern rim.

 

The plateau is mostly used for agriculture. The rainfall at nearby Boorganna Nature Reserve is 1930 mm per year. Mists and fog are common, being exposed to orographic influences from the east.

 

Dairy farms and vegetable plantations are often seen on the plateau. It is a rich farming community with high land prices. On Monday we noted a healthy avocado plantation next to Boorganna Nature Reserve.

 

Within these farms are the occasional original sub tropical rainforest tree. Sometimes a small patch of between five and a hundred trees. Cattle enjoy the shade underneath these original rainforest trees. One of the most common farm trees is the Rosewood (Dysoxylum fraserianum). It's possible that some Comboyne farm trees may be Antarctic Beech, as yet undiscovered.

 

In 1925 the botanist E.C. Chisholm surveyed the remains of the Comboyne rainforests. He wrote that the beech was "extremely rare, although many trees were undoubtedly destroyed during clearing." However, on Monday, our wonderful guide Colin suggests that he has evidence that the beech was common or abundant on the Comboyne plateau in the 19th century.

 

Chisholm's text was read by contemporary botanists and used as evidence for the species' supposed extinction in the Comboyne area. However, the rainforest botanist A.G. Floyd has the species listed at Comboyne in his 1989 publication: Rainforest Trees of Mainland South-eastern Australia, Inkata Press 1989, ISBN 0-909605-57-2

 

The Antarctic Beech at Comboyne show strong regeneration from seed. Here the beech seems mostly confined to stream-side locations. Though there did appear to be a number of trees up the hill (see notes on the photo). As with the population at east Dorrigo, the species grows at unusually low altitudes.

 

These Comboyne populations show the resilience of the species after the plateau was almost entirely cleared in the first quarter of the twentieth century. It is clearly "vagile", that is able to move and distribute in disturbed areas through "mast" seeding. The trees we saw included relic plants of considerable age, as well as mature, young, sapling and seedlings.

 

The Antarctic Beech group (Nothofagaceae) is an ancient type of plant, of great significance to southern hemisphere botanical distribution. This group is often associated with the breakup of the ancient super continent Gondwana.

 

They are currently found in southern South America (Chile, Argentina) and Australasia (east and southeast Australia, New Zealand, New Guinea and New Caledonia).

 

This particular species is found between the Barrington Tops in the south (-32.052, 151.493). To the Lamington Plateau to the north (just over the border of New South Wales in Queensland). (-28.142, 153.115)

 

Now known as Lophozonia moorei. It was previously known for many years as Nothofagus moorei and other names including Fagus moorei. Fagus being the genus of the European Beech (Fagus sylvatica).

 

The Antarctic Beech is usually seen between altitudes of 900 to 1550 metres above sea level. At Comboyne they are found as low as 570 metres. There is a Facebook report of the beech growing on the upper Nymboida river at 520 metres above sea level. Though I've not seen this published anywhere. I've seen them nearby at Mobong Creek at 605 metres altitude.

 

It is not limited to the better quality basaltic soils, such as at Werrikimbe national park. At nearby Mount Banda Banda it grows on soils derived from porphyry, a type of granite. There associate species include the sub tropical Yellow Carabeen and Walking Stick palms. Near Dorrigo it grows beside the Hoop pine.

 

Further north at Cathedral Rock, it grows on adamellite, another granite which produces even less fertile soils. The cool temperate rainforests there are dominated by an expected associate, the Black Olive Berry (Elaeocarpus holopetalus). The Antarctic Beech can become a competitive and viable species in unexpected places within its range.

 

North at the Border Ranges/Lamington National park, the Antarctic Beech grows alongside sub tropical trees like the Bangalow Palm and Black Booyong. (Archontophoenix cunninghamiana & Argyrodendron actinophyllum). Here at Comboyne it also grows next to the Bangalow Palm.

 

There is a record of this species in the Blue Mountains west of Sydney. However, this is considered a "blow-in" from Mount Tomah Botanic Gardens, several kilometres away. There's another record of it from Mount Kaputar on the western plains near Narrabri. I've yet to hear if this 1911 record is accepted by the scientific community.

 

There is a record in New South Wales of the related Lophozonia cunninghamii. However, this is a fossilized stump, some thirty thousand years old. Located in Kościuszko National Park. It's unlikely that it occurs alive in New South Wales. But you never know!

 

The documentation by Bale & Williams of these refugial stands at Comboyne is another interesting chapter of the story of the Nothofagaceae. It gives extra clues regarding paleoclimatic and paleobiogeographic inferences.

 

As these stands of Antarctic Beech are at such low altitudes and in a warmer climate as one might expect. Their potential deterioration in more hot weather in situ may signify further evidence of climate change.

 

Thanks to the botanist Colin Bale for his e-mails, advice and support.

Done