SDMF Newsletter 2001 Warwick

Warwick's Corner

Looking back we often wonder where the year has gone. Time flies and all that stuff. Yes, count me in on that one. I would love to say that we have been fishing every opportunity but that's not true. I do have a very good excuse though.

It all started on a cool May Sunday afternoon. The weather was being kind to the two pheasant shooters and their dogs. Warwick and Ian were enjoying the day out and had covered a fair hunk of the Santoft Forest. They had even put up a couple of birds - hens of course. It was time to start thinking about turning for home, when I suggested to Ian that we do one more block. He said "You go for it. I'll meet you on the next road over." I didn't waste much time getting into this block. Ideal small pines, reasonably open. Might even see a couple of Sambar in this sort of cover. Only 75 metres in, it was obvious there were some deer about. The ground was well cut up by the number of foot prints, and the odd pine tree had been nibbled at. The bark was stripped and fresh gum was starting to ooze. An unwelcome sight greeted me over the next ridge. More tree damage. My brain went into overdrive and I zigzagged over as much of this block as I could, trying to get a handle on what on earth was happening.

This was not normal. The damage was consistent throughout the block. Most of it was fresh. What bugged me most was the amount. I love Sambar deer but it is hard to even like them a little when you see this sort of damage. By the time I met up with Ian on the next road I had totally forgotten we were there to hunt pheasant. (By the way Ian had nailed two very ugly bird-eating cats.) Most of the way back to the car, the conversation revolved around Sambar deer and the pine trees, interrupted by the odd excursion off the road to inspect the blocks we were passing, for tree damage. A surprising amount of damage was visible from the road. The trip home gave us time to reflect on what we had seen. You may be wondering - why all the excitement about a few pine trees being eaten by a couple of Sambar deer? The reason being, historically Sambar normally eat the bark of the young pine trees during the months of July and August. This was late May so one had to wonder several things.
1 - Was there a reason such as hunger or a vitamin or mineral deficiency.
2 - With this amount of damage was it going to carry on till August.
3 - Was it possible to stop the damage without removing the deer.
The next meeting of the S.D.M.F. was little over a week away and I felt something had to be done, so I made tracks back to Santoft for another look around. I didn't learn a great deal but closer examination showed the damage level had started about early May and was still continuing.

On Wednesday, 7th June was the S.D.M.F. meeting.
At the meeting I gave an account of my wanderings and the problem in Santoft Forest re. Sambar deer. I suggested it was a good opportunity for the S.D.M.F. to do some research into why Sambar deer eat pine bark. After a long discussion the meeting agreed to-go along with the theory that the bark eating was because of a vitamin or mineral deficiency. Maybe if we could find which vitamin or mineral they were lacking we could give it to the deer by way of salt or feed blocks. Hopefully stopping the damage to the pine trees in Santoft Forest and any other area in which this occurs.

Peter Neilson-Vold and I were given instructions to price salt and mineral blocks and organise a field trial of these blocks, with a budget of $500. A motion was also passed to fund a 1 hour of helicopter survey of the same area to get an idea of the number of Sambar responsible for the damage.

On the way home from the meeting Ian suggested that I keep notes or a diary of the project, which I agreed to do much to my surprise. I ended up writing over 6 pages of details and putting together a folder with price lists, fact sheets and other relevant information.

The next two days were full on racing around Vets and Stock and Station stores putting together a price list of products available. Deer feed blocks were not available because of machinery breakdown. Further inquiries showed deer blocks are only made to order, I believe, because they are best fed fresh and do not deteriorate. Also different additives can be added to suit requirements, such as vitamins and minerals. Sounded good to me. When I rang the 0800 number for NRM to find out more, the young lady on the other end of the phone asked if I had a problem with deer eating my trees. She was new to the job but most of the enquiries she had, were deer and tree related. She could not help, so put me through to one of their nutrition experts to whom I talked for a good hour. He advised us to contact an Analytical Laboratory to find out what was so important in pine tree bark. I next called several Farm Consultants to see if they had any ideas, or similar problems with domestic stock. This led me to a gentleman by the name of Ian Frame. Ian now runs Agricultural Testing Services Dannevirke. He had no idea why Sambar behaved like this but he was keen to help if he could. He said he would consult with a higher authority and get back to me. Later that night Ian rang back after he had talked with the company experts and the laboratory. The experts suggested a vitamin or mineral deficiency and that maybe the bark should be analysed. If it was possible could we send the lab 2 bread bags full of pine bark - preferably from the trees being eaten.

On Saturday I rang Peter Neilson-Vold about the salt blocks. Peter had a good deal offered in Taihape so it was agreed that he purchase $250 of multi-min and copper and wait for the results of the bark testing before buying the feed blocks. We arranged to meet in Bulls on Wed, 14th June.

On Monday Ian Frame rang to say he had put some time into research, read the books and talked to more experts and the lab technicians. He has come to the conclusion that day light, or the lack of it, has something to do with the absorption of phosphorus, thus the eating of bark - the reason that cattle and horses chew bones, fence posts and trees at the same time of year.

On the Wednesday my wife Lesley, and I picked up the key from the Ernslaw One office in Bulls and met with Peter Neilson-Vold and his truck load of salt blocks. We headed for Santoft Forest and after a look around at some of the damage we proceeded to put out the salt blocks. Suitable sites were found where there was a lot of Sambar sign, and strips of wool pack were poked onto branches as markers for future reference. Ten sites were used. Six of them had multi-min, two had multi-min plus a copper block and two had multi-min plus a magnesium block. While laying the blocks we ran into Brent Rogan, a forest health adviser. We had a good chat with Brent about the tree damage. As the forest is growing on almost raw sand, soil tests show very low mineral content, in particular, copper. He thought our findings from the salt blocks may be interesting. Then Pete and I stripped the bark. It took about eight trees to fill a bread bag, so it took a while to fill two. I didn't feel bad about the damage as we only took bark from trees already damaged. By 6pm the bark was on its way to Hamilton.

On Monday, l9th June I rang Peter. He had surveyed Santoft on foot and checked the salt blocks. One multi-min had been stolen. The only site with fresh sign was one of the copper ones. It appeared all the corners were eaten off, so during the next trip to town, on Friday, I purchased seven copper blocks. It looked like we were onto something.

On Tuesday, 27th June I had an early start for Bulls. I picked up the key and met Craig Langland at the Santoft Forest gate at 9.05 am. Craig is a new S.D.M.F. member and keen to get into the field. We toured a few roads and then found new sites for the copper blocks, marking branches with yellow tape. The yellow was not a good idea as it was very hard to relocate. While returning the key, I found out how the forest workers get foliage samples for testing. They shoot them down with a shotgun. I am not quite sure what size shot is required.

The bark samples are taking longer than expected, so I made several trips to the forest to check the salt blocks. Nothing seemed to be happening. Deer were walking past blocks and totally ignoring them. It was very disappointing after the time and effort everyone had put into it. It did prove one thing. It's not going to be as simple as tossing a few vit's and min's about. In case we do come up with the answer as to what they get from pine bark it is decided to try feed blocks to see if the deer will eat them. We might as well be ready.

Feed blocks were bought, and Lesley and I were off to Santoft once more. These blocks were placed close to the salt blocks already in place. The feed and salt blocks were checked regularly for two months and nothing was eaten, not even a feed block nibbled. Another bright idea turned to mud.

The results of the feed and mineral analysis of the pine bark arrived which created more questions than it gave answers. A copy of the report appears below.

I now know that the more I dig into this problem I am reminded how little we know about Sambar deer. Some questions that have come from this study are:
1 - Is it a vitamin / mineral deficiency?
2 - Is it a food quality problem?
3 - Have pine tree producers developed a more palatable tree?
4 - Is it a depraved appetite?
5 - Or is it a learned behaviour problem?
6 - If the problem deer were removed, would the deer that move in, repeat this behaviour?
7 - If it is a food quality problem, do we overcome it by planting better food ?

Answers are desperately needed as the problem has not gone away, but continued for 12 months, not the normal 2 months of the year.

Hunting at the moment does not seem to work. First, the block was cut in half to double the days hunted. This did not result in more animals being taken, so last season we doubled the number of hunters again. The required number of animals still were not taken. If hunters don't take hinds and young animals the Foundation will have to look at other means of controlling high populations. Lower populations damage less trees and until we can find the reason for bark eating, high populations of Sambar will not be tolerated by foresters and tree farmers.

If you know the reason, or have some scientific evidence, or a magic wand, give me a call. I'm open to suggestions.

Might see you in the bush - so for now, I wish you safe and happy hunting.

Warwick

Deer ring barking trees in the Santoft Forest

1. The usual reason for ruminants to exhibit "depraved appetite" behaviour is a deficiency of either P or Na.

2. The analysis of the pine tree bark shows very low levels of P. but adequate levels of sodium. Protein, copper, molybdenum and selenium are also very low. These deficiencies, combined with the high levels of acid detergent fiber (ADF) mean that the bark is unlikely to contribute to the diet; its low digestibility will mean that even those nutrients present in seemingly adequate amounts are unlikely to be released.

3. The conclusion is that the bark is being eaten in response to a depraved appetite syndrome rather than as a source of anything specific.

4. Although the forest is on the west coast and will therefore receive onshore, salt-laden winds, it does not follow that the interior will receive much, if any, sodium. Foliage is very efficient at stripping salts out of the wind, so it is likely that little salt is deposited beyond the windward row of trees.

5. Pasture plants grown in reduced light tend also to contain low levels of nutrients. Farm forestry enterprises fail for that reason there is very little time between the period stock have to be excluded to avoid tree damage and the time that feed quality declines below the levels needed for animal production, so the chance to make animal income to offset reduced tree income is too short.

6. Production forests with high tree densities and no clearings in which good quality forage could grow are unlikely to provide good quality forage for deer, especially pregnant or lactating hinds.

7. The ring barking behaviour is probably a response to this situation - especially if the forest is developing, and the area of potentially good quality browse is decreasing annually.

8. Further samples of material being eaten by the deer (not the bark) should shed some light on the specific deficiencies being encountered. From this a management program to supplement their diet and avoid the depraved appetite could be developed.

P W (Paddy) Shannon
Technical Director
ACS (2000) Ltd.
Hamilton