Clearing codes

My name is Seamus Batstone and this is Scott Devaney. Today we’re going to do a tree stem density measurement using a rectangular plot.

The plot’s going to be 100 metres long and it’s going to be 4 metres wide. So we’re going to roll out a central line tape 100 metres long, and then we’re gonna use a 2 metre long stick to count trees either side of that line.

The 100 metres by 4 metres wide is 400 square metres, which is 1/25th of a hectare. We’re going to multiply the number of trees we count in that plot by 25 to get our number per hectare.

Okay so the first part of measuring our tree density is we’ve got to get a measuring stick. So this stick I’ve already cut it down to 2 metres long. We want a 2 metre long stick.

The other thing that we need to know is diameter at breast height is measured at 1.3 metres above the ground. So as you can see, I’ve already put this mark 1.3 metres along this stick so when I hold it there, I know that I’m in the right place to measure diameter.

In terms of diameter for the eucalypts, Corymbias, Lophostemons and Angophoras in coastal areas, they’ve got to be 40 centimetres or more diameter at breast height to be a mature tree. Under that, they’re immature.

In non-coastal areas, out west, if they’re 30 centimetres or more diameter at breast height then they’re mature; below that, they’re immature.

For all other species, if they’re over 20 centimetres diameter at breast height, then those trees are mature. I’ve actually put those graduations on my stick. I put a 20 centimetre graduation, a 30 centimetre graduation if I’m working in western areas and a 40 centimetre graduation for when I’m working in coastal areas.

And we’ll use those shortly when we’re doing our transect.

So we found a representative area. This is a perfect point for our transect. To do the transect the hundred metres long you’ll either need 100 metre long tape or 100 metre long piece of rope, as long as you’re pretty certain about how long it is.

What we’re going to do is take a GPS point at the start of the transect and at the end of the transect. And the actual transect line we’re going to take using a compass. That’s to ensure that it stays straight.

So I’ll take my transect now. So I’m going to tie this off to make it easy on myself. I’ll tie it off close to the ground. Now just remember I’ve got to go about 40 centimetres over 100 metres because of I’ve lost that bit in tying it off. It’s a good idea to look back and just make sure that your line’s straight.

Scott’s gonna give me a hand with booking today. It’s much easier if you’ve got an offsider to book them down as you yell them out. Righto Scott we’ll get into it.

Okay so that’s a that’s a eucalypt. Remember to yell out the genus as you go. That’s a eucalypt, that’s in, Scott, that’s an immature tree. That’s an acacia but it’s dead, we won’t count that one, Scott. That’s an acacia, that’s an immature tree and that’s in. There’s a Lophostemon, Scott – that’s an immature tree, it’s in. This little Lophostemon, we better see if he’s over 2 metres tall; 2 metres, so he’s counted as in.

This one’s pretty close to being mature. First off, we’ll just work out where 1.3 metres is – so that’s 1.3 metres on this tree – and then we’ll check his diameter. There’s our 40 centimetre graduation, and I can see that he’s just over 40 centimetres so he’s counted as a mature tree.

That’s an immature tree, he’s just in. We’ll just keep going like this until we get to the end of our 100 metre transect.

Okay, Scott, we’ve come to the end of our transect. We’ll tally these figures up now.

Rightio let’s have a look. We’ve got 3 mature trees there in that eucalypt, Corymbia, Angophora, Lophostemon genus. So that’s 3. We didn’t get any other mature trees from another genus so the total of mature trees is 3.

We got 39 eucalypt, Corymbia, Angophora, Lophostemon that were immature, counted. And we got 13 other species. So that gives us a total immature trees of 52 in our transect. You multiply those by 25, so 52 times 25 gives us an estimated 1,300 immature trees per hectare and 75, well 3 times 25 gives us 75 mature trees per hectare. And that’s our tree density.

Some of the key things to remember are:

• use a compass when you’re rolling out your tape or your rope just so that you keep a straight line
• take a GPS point at the start and at the finish to show where you were
• take some photographs of the site
• remember to look up what a mature tree means in your area using the code that you’re using.

Accepted development vegetation clearing codes allow Queensland landholders to manage specific low-risk clearing activities without the need to apply for a development approval.

When working under a code, landholders are required to follow specific practices and meet certain requirements – for example, identifying any habitat trees in the area – before commencing any clearing activities.

All habitat trees must be retained.

There are also requirements to:

• not damage a habitat tree
• not mechanically clear within 5 metres of a habitat tree
• not spray herbicide within certain distances from a habitat tree
  and
• not leave woody debris within 2 metres of a habitat tree.

By definition under the accepted development vegetation clearing codes, habitat trees include:

• living trees with one or more visible hollows of 10 centimetres or more in diameter and positioned at least 2 metres above the base of the tree
  and
• any tree that contains an active bird’s nest or the nest of a raptor or other bird that uses the same nest each year.

Habitat trees are an important component of our regional ecosystems. They provide breeding sites, shelter, refuge and living places for numerous native animals.

When undertaking clearing on your property, be sure to identify and retain habitat trees, and adhere to any required buffer distances in the codes.

For more information on vegetation management or the accepted development vegetation clearing codes, contact the Department of Natural Resources and Mines.