Investigating White Cypress Pine Clearance through scientific theory and a field day

By: Rachel Hill, October 12, 2009

The topic of Invasive Native Scrub (INS) continues to be a contentious one and the response to my two previous articles titled: White Cypress Pine: Friend or Foe? and Clearing up the White Cypress Pine Debate, on this issue proved this point. At Liverpool Plains Land Management, we strive to give advice to the community and undertake better land management practices which are based on sound science. This is the approach that we are taking with the INS clearance trials being undertaken by the Nandewar Range Landcare Group on Barry Keen’s “Braefield” property.

The basis for experimental science is ‘scientific method’. There are several steps or parts to scientific theory. 

1. The definition of a problem. In the case of White Cypress Pine, the problem is that in many areas it has become invasive and is spreading prolifically resulting in poor soils, a loss of ground cover, erosion problems and loss of productivity.
2. Forming a hypothesis e.g. that the clearance of pine results in improved soils and improved ground cover. Note, that for the budding scientists out there, that in hypothesis testing we attempt to disprove the null hypothesis (H_o). So for the White Cypress Pine clearance trials, the null hypothesis would state that pine clearance has no impact on soil health and ground cover and therefore we would be trying to demonstrate that this is untrue.
3. Testing the hypothesis. This is usually done by conducting a scientific experiment which involves collecting either quantitative or qualitative data. For example, by comparing sites an uncleared area of White Cypress Pine with areas which have been cleared at different time intervals. 
4. Analysing the data and interpret the results, so that you can reject or accept the hypothesis.

The steps in the scientific method have been followed closely in the White Cypress Pine clearance trials at “Braefield” by the Nandewar Range Landcare Group.

The project has been funded by Woolworth’s as part of their Sustainable Farming Drought Recovery Program.

The aim of these trials was to help clear up some of the uncertainty around not only the impact that INS has on the environment and land productivity, but to measure the success of clearing the Pine trees to improve the soil and other environmental factors. There have also been studies on the thinning of White Cypress which has had varying levels of success as a method of control. 

The return of good groundcover only 4 months after Invasive Native Scrub (INS) is removed

For those of you interested in using thinning as an option there are some interesting papers online by authors: J Knott, and R Horne and G Robinson of Australian Forestry. This has not been tested in these particular trials, but could definitely be addressed at the Nandewar Field day outlined below.

The results of the Pine Clearance trials by the Nandewar Range Landcare Group have been published in a preliminary report by Judi Earl of Agricultural Information and Monitoring Services. As many farmers will suggest, although science has its place in land management, there is also great value in basic common sense, visual observations over time and the use of trial and error. For those of you interested in observing the results of these trials first hand, as well as looking at several other successful projects, the Nandewar Range Landcare Group are conducting a field day with support from LPLM on 19^th October. 

This day will involve a tour of the White Cypress Pine clearance plots and several presentations by people experienced in this field. The meeting point is on Johnson Rd at 2pm. To get there (from Gunnedah): Follow the Kelvin Road to the Manilla-Boggabri Road intersection and turn left towards Boggabri, continue for ~1km, then turn right into Johnson’s Road.

The day will conclude with a barbeque at Matt Carter’s “Myall Springs”. If you are interested in attending, please contact Rachel Hill on: 6741 8316.