Monday, 19 November 2012

Local Big Trees

On Saturday Jacqui Mitton hosted Derek McIntosh (who runs the National Register of Big Trees) around the local area (with us being part of the group out of general interest) looking at local big trees identified through local knowledge and contacts during the planning for the day. In all we looked at and recorded 6 trees each of different species. All are within an area where Grenfell is considered to be the local town. Grenfell is within the NRBT's designated region of Central NSW.

'Biggest' trees and Points Allocation

The biggest trees of a particular species are given 'champion' status and this can be at Region, State and National levels. To enable consistent comparison between all trees regardless of species points are calculated based on the trunk circumference at 1.4 metres from ground level, tree height and average crown spread. The formula for determining total number of points for each tree is:

  • Trunk circumference (girth) at 1.4 metres from ground-level in metres multiplied by 39.37 PLUS
  • Tree height in metres multiplied by 3.28 PLUS
  • Average crown spread in metres multiplied by 0.82

The resultant total from the above process enables direct comparison with trees listed in both the Australian NRBT and the American Forests register. The calculation process gives primary weighting to the girth measurement, secondary weighting to height and tertiary weighting to crown spread.

Biggest Trees in Australia and the United States of America

To give perspective to the size of our local trees:
  • The largest tree presently listed on the Australian NRBT is a Mountain Ash (Eucalyptus regnans) located near Geeveston in Tasmania. Its total points are 1,087 calculated off the tree's circumference of 20.45 metres, height of 81 metres and crown of 20 metres
  • The largest tree on the American Forests register is a Giant Sequoia (Sequoiadendron giganteum) located in Sequoia National Park, California. Its total points are 1,321 calculated off the tree's circumference of 25.9 metres, height of 83.5 metres and crown of 32.6 metres.

Local Trees we Visited on Saturday 17 November 2012

All 6 of the trees we checked out on Saturday are listed below in the order seen. All are on private property and we were grateful to the owners for giving us permission to access their land to see, photograph and measure the trees. The names of the owners and their properties are not shown below in the interest of privacy.
The following is given for each tree:

  • Common and scientific name
  • Location listed by Parish, Locality and Shire
  • Photograph NB: The photographs unfortunately don't do real justice to seeing these trees 'live'
  • Measurements in metres: Circumference, height and crown
  • Points
  • Status in terms of the National Register of Big Trees

Western Grey Box (Eucalyptus microcarpa)

Location (Parish/Locality/Shire): Maudry / Ooma / Forbes

Trunk circumference: 5.3 metres
Height: 26 metres
Crown: 26
NRBT Points: 315
NRBT Status: New National champion

Red (Mugga) Ironbark (Eucalyptus sideroxylon)

Location (Parish/Locality/Shire): Maudry / Pinnacle / Weddin

Trunk circumference: 5.61 metres
Height:  21 metres
Crown: 26
NRBT Points: 311
NRBT Status: New National champion

White Cypress Pine (Callitris columellaris)

Location (Parish/Locality/Shire): Maudry / Pinnacle / Weddin

Trunk circumference:  3.71 metres
Height:  17 metres
Crown: 18.2
NRBT Points: 217
NRBT Status: New National champion

Lemon-Scented Gum (Eucalyptus citriodora)

Location (Parish/Locality/Shire): Yuline / Glenelg / Weddin

Trunk circumference:  4.38 metres
Height:  22 metres
Crown: 26
NRBT Points: 265

Kurrajong (Brachychiton populneus)

Location (Parish/Locality/Shire): Bimbi / Bimbi / Weddin

Trunk circumference:  5.16 metres
Height:  16 metres
Crown: 26
NRBT Points: 277
NRBT Status: New National champion

River Red Gum (Eucalyptus camaldulensis)

Location (Parish/Locality/Shire): Yambira / Bumbaldry / Weddin

Trunk circumference:  8.1 metres
Height:  30 metres
Crown: 29
NRBT Points: 439
NRBT Status: New Central New South Wales champion

Equipment Used by Derek

Here's a list of the equipment used by Derek as part of his process of recording details of the trees:

  • Pen and notebook
  • Digital camera
  • GPS device
  • Distance calculator, which includes the ability to calculate the height of a tree

Sunday, 11 November 2012

Distinguishing Bees V Flies V Wasps

For a while yesterday morning we were watching honey bees foraging in one of the flowering Kurrajong trees near the sheep yards. The tree has a very heavy load of flowers and in this photograph is a single honey bee accessing pollen and nectar:

We noticed another species of insect being quite aggressive to the honey bees, and managed to capture the image of one of them ... below:

To appease our curiosity in determining the species of the aggressor we sent an email to members of the team room set up post attendance of the natural beekeeping course in Sydney earlier in the year. We asked whether any of the members knew what it was and attached the above photo. Within a couple of hours Louise Y responded saying that it was some type of hover fly and shared a hyperlink to the Queensland Government Department of Primary Industries and Fisheries publication titled "The Asian Honey Bee - A Guide to identification" located on the Animal Health Australia website. The document in fact is an excellent summary of the main things to look for in distinguishing bees from flies and wasps. Some information about Rainbow Bee-eaters is also contained in the publication, including the fact that they have communal roosts in the same location each night.

Saturday, 10 November 2012

Big Trees on Ochre Arch

In yesterday’s local paper (The Grenfell Record) there was an article submitted by Jacqui Mitton alerting readers that next weekend Derek McIntosh, Co-ordinator, National Register for Big Trees was going to be in the area and will be looking specifically for large White Box (Eucalyptus albens) or Western Grey Box (Eucalyptus macrocarpa) to place on the register. We checked out the Register website, learned the measurement guidelines (NB: we used method 1 to determine tree height ... quite a bit of fun, actually) and headed off around the farm to see what we could find that might be suitable for registration. One of the biggest challenges in the process when it comes to identifying possible eligible eucalyptus trees is finding ones that are still a single stem at the stipulated circumference measurement height of 1.4 metres. Our guess is that only one in ten on our place meets this criterion.

Below are the biggest trees of the main species we have on our farm. Given that ‘size is all relative’ the ones we’ve listed may well be dwarfed by same-species trees on other properties; especially given that much of our farm has been cleared since white-fella occupation of the area and the fact that our soils are comparatively light and low in fertility. That said we reckon our White Cypress-pine tree would give others a fair run for their money! 

Kurrajong (Brachychiton populneus), NE corner, Amphitheatre Paddock

Trunk Circumference: 3.3 metres
Tree Height: 12.7 metres
Average Crown Spread: 15.5 metres

White Box (Eucalyptus albens), Gully edge near southern boundary, White Box Paddock

Trunk Circumference: 1.5 metres
Tree Height: 19.3 metres
Average Crown Spread: 12.3 metres

Blakely’s redgum (Eucalyptus blakelyi), West of track 1/3 way from entrance gate, White Box Paddock

Trunk Circumference: 1.8 metres
Tree Height: 18 metres
Average Crown Spread: 14.7 metres

Western Grey Box (Eucalyptus macrocarpa), near tourmaline site, Lookout Rock Paddock

Trunk Circumference: 2.2 metres
Tree Height: 21 metres
Average Crown Spread: 15.3 metres

Yellow Box (Eucalyptus melliodora), centre southern boundary, Valley Paddock

Trunk Circumference: 3.9 metres
Tree Height: 27.8 metres
Average Crown Spread: 17.7 metres

White Cypress-pine (Callitris glaucophylla), centre west, Big Pine Paddock

Trunk Circumference: 3 metres
Tree Height: 19.3 metres
Average Crown Spread: 15 metres