### 2.17.1.1. Maintenance Respiration[¶](#maintenance-respiration "Permalink to this headline")

Atkin et al. (2016) propose a model for leaf respiration that is based on the leaf nitrogen content per unit area (\\(NS\_{narea}\\) (gN m 2 leaf), with an intercept parameter that is PFT dependant, and an acclimation term that depends upon the average temperature of the previous 10 day period \\(t\_{2m,10days}\\), in Celsius.

(2.17.1)[¶](#equation-17-46 "Permalink to this equation")\\\[CF\_{mr\\\_ leaf} = i\_{atkin,pft} + (NS\_{narea} 0.2061) - (0.0402 (t\_{2m,10days}))\\\]

The temperature dependance of leaf maintenance (dark) respiration is described in Chapter [2.9](https://escomp.github.io/ctsm-docs/versions/master/html/tech_note/Photosynthesis/CLM50_Tech_Note_Photosynthesis.html#rst-stomatal-resistance-and-photosynthesis).

(2.17.2)[¶](#equation-17-47 "Permalink to this equation")\\\[CF\_{mr\\\_ livestem} \\\_ =NS\_{livestem} MR\_{base} MR\_{Q10} ^{(T\_{2m} -20)/10}\\\]

(2.17.3)[¶](#equation-17-48 "Permalink to this equation")\\\[CF\_{mr\\\_ livecroot} \\\_ =NS\_{livecroot} MR\_{base} MR\_{Q10} ^{(T\_{2m} -20)/10}\\\]

(2.17.4)[¶](#equation-17-49 "Permalink to this equation")\\\[CF\_{mr\\\_ froot} \\\_ =\\sum \_{j=1}^{nlevsoi}NS\_{froot} rootfr\_{j} MR\_{base} MR\_{Q10} ^{(Ts\_{j} -20)/10}\\\]

where \\(MR\_{q10}\\) (= 2.0) is the temperature sensitivity for maintenance respiration, \\(T\_{2m}\\) (°C) is the air temperature at 2m height, \\(Ts\_{j}\\) is the fraction of fine roots distributed in soil level _j_.

Table 2.17.1 Atkin leaf respiration model intercept values.[¶](#id4 "Permalink to this table")  
| Plant functional type
 | \\(i\_{atkin}\\)

 |
| --- | --- |
| NET Temperate

 | 1.499

 |
| NET Boreal

 | 1.499

 |
| NDT Boreal

 | 1.499

 |
| BET Tropical

 | 1.756

 |
| BET temperate

 | 1.756

 |
| BDT tropical

 | 1.756

 |
| BDT temperate

 | 1.756

 |
| BDT boreal

 | 1.756

 |
| BES temperate

 | 2.075

 |
| BDS temperate

 | 2.075

 |
| BDS boreal

 | 2.075

 |
| C3 arctic grass

 | 2.196

 |
| C3 grass

 | 2.196

 |
| C4 grass

 | 2.196

 |

Note that, for woody vegetation, maintenance respiration costs are not calculated for the dead stem and dead coarse root components. These components are assumed to consist of dead xylem cells, with no metabolic function. By separating the small live component of the woody tissue (ray parenchyma, phloem, and sheathing lateral meristem cells) from the larger fraction of dead woody tissue, it is reasonable to assume a common base maintenance respiration rate for all live tissue types.

The total maintenance respiration cost is then given as:

(2.17.5)[¶](#equation-17-50 "Permalink to this equation")\\\[CF\_{mr} =CF\_{mr\\\_ leaf} +CF\_{mr\\\_ froot} +CF\_{mr\\\_ livestem} +CF\_{mr\\\_ livecroot} .\\\]

