Base hurricane extension v2.0 question

[蔡良苑]

Dear users and developers,

I'm using the Base Hurricane Extension v2.0, but right now I'm confused about whether the dead biomass is transferred to the dead wood carbon pool or simply removed from the landscape after the hurricane kills the trees.



Thanks a lot,
Liangyuan Cai

[Robert Scheller]

Liangyuan,

Biomass Hurricane v2 (Base Hurricane has been retired) is not yet ready for release; I can't guarantee full functionality at this time.

To answer your question:  If you're using NECN succession or Biomass succession, the default disturbance assumption is that all dead materials ends up on the forest floor.  Only harvesting (removal for wood products) and fire (volatilization) behave differently.  

If you're using a different succession extension, the behavior may differ.  DGS, PnET, or ForCS developers:  What are the assumptions for post-disturbance dead material?

Cheers,

Rob

[Caren Dymond]

Hi

In ForCS the transfers of live and dead material is controlled by users in "Disturbance Matrices". We haven't tested with Hurricane, but using Base Wind it would look something like this:

DisturbOtherTransferDOM 

>>  Disturbance     From    To      To      To
>>  Type                 DOM     Air     DOM     FPS
>>  -- -------- --------------------------------------------------------  -     

       wind                  8         0.0     0.3     0.5
       wind                   9        0.0     1.0     0.0     

Where DOM and Soil pools 8 and 9 are Merchantable-sized snags and Snag branches or small dead trees.  In this example 50% of the standing snag stems are harvested as a result of the wind disturbance, 30% become Coarse Woody Debris. The remainder is left as snags (presumably for wildlife habitat or something). All of the branches and small dead trees goes to the Aboveground Fast pool aka small woody debris.

This functionality allows simulation of post-disturbance logging (To FPS = Forest Product Sector) without a harvest extension. It also allows burning of dead material (To Air column) if that's done, for example to create planting spaces.

There's a similar table for Biomass pools that tells ForCS what to do with cohorts the wind extension says are killed. Note you can't affect live cohorts through ForCS that are not affected by the disturbance in some way.

DisturbOtherTransferBiomass

>>  Disturbance     From           To      To        To
>>  Type                  Biomass     Air     FPS     DOM
>>  -----------------------------------------------------------------------------------  

      wind                               1       0       0.7      0.3
      wind                                 2       0       0          1
      wind                                 3       0       0           1
      wind                              5        0 0      1
      wind                              6       0  0       1

>> Biomass Pools
>> Indices to be used when referring to biomass pools
>> 1. Merchantable wood
>> 2. Foliage
>> 3. Other wood (branches of large trees and small trees)
>> 5. Coarse Root
>> 6. Fine Root

Similar functionality is accessible for harvest prescriptions, fire severity, drought, and others.

all the best

Caren