343 | | * Around r7124 we think we understand this saturation. GPP is the input of carbon. We can only allocate to tissue if we have enough N. If we don't, it goes to reserve pool. If we have too much in the reserves, then we reduce GPP with sugar loading. Higher LAIs will initially result in higher GPP but if the system lacks N to allocate the feedback through sugar loading may reduce the GPP on the long term. The model needs a way to "burn off" the GPP that could be allocated. Leaching of labile carbon to the soil (thought to be responsible for up to 20-30% of the NPP - textbook by Chapin 2012) comes to mind. As leaching has not been implemented yet, we could add leaching artificially by turning over the roots. So now we have high GPP, same amount of C goes to tissue, but rather than the excess going to the reserves (and decreasing GPP through the sugar loading) it turns over the roots. This could also increase the soil carbon, which is still desirable around r7113. |
| 343 | * Around r7124 we think we understand this saturation. GPP is the input of carbon. We can only allocate to tissue if we have enough N. If we don't, it goes to reserve pool. If we have too much in the reserves, then we reduce GPP with sugar loading. Higher LAIs will initially result in higher GPP but if the system lacks N to allocate the feedback through sugar loading may reduce the GPP on the long term. The model needs a way to "burn off" the GPP that could not be allocated. Leaching of labile carbon to the soil (thought to be responsible for up to 20-30% of the NPP - textbook by Chapin 2012) comes to mind. As leaching has not been implemented yet, we could add leaching artificially by turning over the roots. So now we have high GPP, same amount of C goes to tissue, but rather than the excess going to the reserves (and decreasing GPP through the sugar loading) it turns over the roots. This could also increase the soil carbon, which is still desirable around r7113. |