Foresty fertiliser poisoning water

lostexpectation

When I heard about this a couple of weeks ago I was like, forest needs fertiliser??? OK a bit naive trees are just big plants...

but apparently I hear forestry is one of main reason for fertisler posioning in our rivers, especially when the forest is cut because the ground under the forest can't absorb the ferisler so it all leaks out...

am I right in what im paraphrasing just trying to start a conversation about it.

Rovi

As far as I know, there's very little 'fertilizer' used on forestry. A bit of rock phosphate perhaps at the very early stages, but that's about it.

Again as far as I know, the major pollution concern is the acidic nature of the rain water run-off that comes from pine/spruce forests.

I'm sure someone much more expert will be along shortly.

.

road_high

lostexpectation wrote:

When I heard about this a couple of weeks ago I was like, forest needs fertiliser??? OK a bit naive trees are just big plants...

but apparently I hear forestry is one of main reason for fertisler posioning in our rivers, especially when the forest is cut because the ground under the forest can't absorb the ferisler so it all leaks out...

am I right in what im paraphrasing just trying to start a conversation about it.

They spread a lot of stuff like rock phosphate on it. Think they even use helicopters! Makes sense as a lot of forestry is set up on low fertility soils i.e. side of mountains! And rainfall and runoff is likely to be higher in these areas.
And of course trees need to the same nutrients (NPK) like any other plants!

Occidental

Phosphates are used in large quantities in poor soil areas. These tend to be bogland and hillsides and are normally associated with Conifer and Birch plantations(the soil being too poor, wet or exposed for most deciduous trees). The problem can also be added to further by trenching for mounding and also by drainage channels.

The_Conductor

While forestry in the past may have been a polluter to a certain extent, it is governed by regulations far exceeding those for normal farm practices.

There is no longer (and has not been for several years) spreading of fertiliser by helicoptor in Ireland. The two largest issues with this were 1. Drift and 2. Cost.
The last time I am aware of helicoptors being used was about 8 years ago (Greenbelt trialled this around 1997/98 in the North West).

Vis pollution of waterways- first of all rainwater is naturally acidic- so stating that rainwater run-off from forestry plantations is acidic is a bit of a misnomer.
Secondly- a lot of forestry plantations are on acidic land already- and the fertilisers most commonly used in those conditions are UMP (unground mineral phosphate) and Lime. This combination is strongly alkaline, not acidic.

Thirdly- there is a buffer alongside any waterways (roadways, overhead wires etc) where you are not allowed to plant- for the purpose of minimising these problems- these buffers are normally sward. The buffer zone varies, but typically would be 3 meters to either side of a minor stream. There is none of the planting to the high water mark that environmentalists would have you believe.

Pollution- as it does occur- is more through the initial afforestation of the land and then 40 years hence the harvesting operations.

To suggest that somehow forestry run-off is a massive negative factor, is to display an ignorance of the fact that the presence of forestry actively minimises run-off by evapotranspiration from the foliage and by locking water into the root systems- reducing run-off over 15 fold that of some arable crops.

I am not an advocate of monoculture of sitka spruce that foresters/farmers in this country seem to adore on a number of grounds though- including:

1. Should a disease arise which favoured sitka, our forestry industry would be decimated in one blow.
2. These are not native species (native to the western states of the US & Canada).
3. These are not particularly high value timber crops, being relatively low weight baring and not entirely suited to the building industry (unlike Scots Pine (red deal) which is a native species and has a load baring index about 2.4 times that of sitka)
4. Having large blocks of similarly aged trees in geometric patterns on our mountainsides does not look good on the landscape.
5. Having a monoculture of trees means they age at the same rate and when time comes to harvest the place looks like a lunar landscape for 10 years
6. We have this preoccupation with only planting trees on the most marginal of land, and then moan when they are not up to scratch. In any other country forestry is regarded as an agricultural crop to compete with other land uses- not as a place to dump trees when the sheep even refuse to feed on the hillsides. Its no bloody wonder that our forests need the odd bit of fertiliser.....

Attitudes are changing though- you can now use birch and a few other native species in broadleaf mixtures, where you could not 5 years ago. These useful additions- while diversifying the nature of the forests are also providing habitats for many woodland creatures that we once feared were dying out.

The forestry debate in Ireland is hindered by our history- in our past the only people who had the money, time or inclination to practice forestry were the landlords (and virtually all mature standing broadleaves in the country are as a result of their interventions). The advent of the travelling charmen in the 18th-19th centuries and the destruction they visited on the few remaining natural woodlands was siezed upon as a land clearance exercise by many (including the British army who claimed Irish insurgents used the woods as hideouts). When we finally got our independence and lands were redistributed- it almost became a badge of honour to chop down what remaining trees there were- and remove those symbols of landlords and their hold on the country. It is from this historic mayhem that we have increased our forestry base from about 1.4% in 1925 to around 10.5% today (still marginally less than 1/2 the European average though). What we really need to do now though is move away from those sodding monocultures of Sitka Spruce, and focus on our native species and see how we can develop both a "native" forestry industry and also use it as a manner to both improve and generate new farm industries and stimulate rural economies.

Shane

Fanny Cradock

Nice post smccarrick.

However, I think you'll find that the current grant and premium scheme does not offer any financial assistance for pure Sitka spruce monocultures. Because of this, I can't imagine any farmers being interested in planting monocultures of Ss. In similar manner, Coillte are bound by regulations that call for mixtures of species to be planted, e.g. a 10% broadleaf requirement on suitable sites etc.

As for the use of clearfell systems, I'd agree that they are ugly. Yet there is a growing interest in using shelterwood systems - which are multi-storied and uneven aged and target specific trees for extraction - rather than chopping everything down. The problem with these systems is that they require a high degree of specific skill/ familiarity and time.

Unfortunately, because of the extremely good suitability of Sitka spruce in this country, which results in very low rotation periods (albeit producing wood with lower strength properties than slower growing SS of other countries) and reasonable financial returns, it will remain the dominant tree.

I hope that as attitudes towards forestry and the role of agriculture changes, land traditionally used for pasture, crops etc. will become available to forestry and diversity will increase. In fact this is already happening. One caveat though: I personally believe that much of the farm forestry being planted out there is done so to procure the premiums and are not planted with any intention of producing a decent final crop. As farm forestry is a new concept here - spurred on with grant/premiums - I wait to see how committed many of the farmers will be to taking the required steps (e.g. thinnings etc.) to produce a good crop.