Chip softwood

[renewablejohn]

You could ring bark the trees then harvest as required once they have dried in situ. The downside is the increased fire risk of tinder dried trees. I first saw the method used at an Austrian biomass plant very successfully. I now use the technique using a felling head and heizohack chipper for biomass harvesting in woodlands that need thinning.

[Farmwood]

You could ring bark the trees then harvest as required once they have dried in situ. The downside is the increased fire risk of tinder dried trees. I first saw the method used at an Austrian biomass plant very successfully. I now use the technique using a felling head and heizohack chipper for biomass harvesting in woodlands that need thinning.

 

That sounds a damn good idea:thumbup1:. Any chance you could share your wisdom with me on this technique:001_rolleyes:

 

You say a felling head can you explain what that is. Is it a hydraulic cutter head for a 360.

 

What model of heizohack do you use and could you recommend a model that would suit this job.

 

In your experience, once you have ring barked them how long on average is it before they are harvestable:thumbup:

[renewablejohn]

Farmwood

 

My felling head is a kesla 19G which replaces my standard grapple head on the forwarding trailer crane but can be used on a 360 if needed. I use on the forwarding trailer crane as you can do a higher first cut due to the reverse boom on the kesla crane. Its basically a cutting blade attached to a grapple claw but cuts upto 8 inches ideal for tree thinning.

We have a heizohack 6-300 with a G30 screen which is ideal for the job as it fits on the 3 point link so ideal for getting in the woods. The bigger machines are on wheeled trailers which then involves dragging trees to roadside.

The ring bark approx 6 inch is taken off before the sap starts to rise (upto the end of feb) and we can harvest the first cut by Sept of the first year taking out the tops. The remaining tree is harvested June to August the following year depending on weather. ie only harvest on dry days.

Where not concerned with bulk biomass collection for power stations but quality dry biomass production which will store over the winter without going mouldy.

[WFWales]

Here you go...

 

Dry softwood is about 400kg per m3 and has a CV of 18.5 MJ per kilo (5.1 kWh per kilo). i.e. each cubic metre is just over 2000kWh.

!

 

5.1 kWh per Kilo is right for 0% moisture content but...

at 20% you get 4kWh and at 30% it drops to 3.4

 

Source: The Carbon Trust - The Biomass Heat accelerator: Assumptions and Scenarios

 

Cheers

 

M

[Farmwood]

Sorry for the delay in coming back on again, I have been away at the Highland Show for a few (wet) days.

 

I think I have the idea of it now.

 

I would like to thank everyone who has contributed to the post as you have been very helpful.

[Woodworks]

For calorific values of various fuels try this site.

Typical calorific values of fuels

[openspaceman]

5.1 kWh per Kilo is right for 0% moisture content but...

at 20% you get 4kWh and at 30% it drops to 3.4

 

This is about right for biomass in general and hardwoods but pine has higher lignin and if we are talking chipped wood rather than whole trees I think it would be 5.2 @10% mc wwb

 

Source: The Carbon Trust - The Biomass Heat accelerator: Assumptions and Scenarios

 

They base their working on 18.6MJ/kg oven dry, a figure used in the stove community for biomass in general. It's so specific a figure that I think the writer trawled it from past papers or an internet search rather than anything empirical.

[Farmwood]

Glenlyon Woodfuel Initiative: Ring barking and Sour felling- Let transpiration dry your wood.

 

I have come across this if anyone else is interested

[renewablejohn]

Glenlyon Woodfuel Initiative: Ring barking and Sour felling- Let transpiration dry your wood.

 

I have come across this if anyone else is interested

 

The one point that report does not stress is timing of any ring barking operation. I cannot find it at the moment but an Austrian report highlighted the critical nature of timing of the ring barking in respect of sap rising or falling and the knock on effect of the root structure and potential for regrowth. Maybe someone else can shed light on this.

[tree monkey]

could you not use a log burning boiler like skyhucks and chip the brash ?would that be cheaper than buying all that kit ?