1. Plant respiration

1.1 Autotrophic Respiration

The model treats maintenance and growth respiration processes separately (Lavigne and Ryan, 1997¹; Sprugel, et al., 1995²).

1.1.1 Maintenance Respiration

Maintenance respiration (MR) is a function of temperature and tissue N concentration (Ryan, 1991³) for live biomass (excludes dead stem and coarse root pools) (Thornton and Rosenbloom, 2005⁴). Rates for aboveground pools are based on the prognostic 2-meter air temperature, and rates for belowground pools (fine and coarse roots) depend on fractional rooting distribution with depth and the associated prognostic soil temperatures.

Implemented in subroutine: MaintenanceResp

\[ \begin{equation} F^C_{mr,leaf} = (lmr_{sun} \times lai_{sun} + lmr_{sha} \times lai_{sha}) \times C_{umolCO2\_to\_gC} \end{equation} \]

\[ \begin{eqnarray} \label{eqn_mr} F^C_{mr,livestem} &=& S^N_{livestem} \times br_{mr} \times q_{10}^{\left(\frac{T_{2m} - T_{frz} - 20}{10}\right)} \\ F^C_{mr,livecroot} &=& S^N_{livecroot} \times br_{mr} \times q_{10}^{\left(\frac{T_{2m} - T_{frz} - 20}{10}\right)} \\ F^C_{mr,grain} &=& S^N_{grain} \times br_{mr} \times q_{10}^{\left(\frac{T_{2m} - T_{frz} - 20}{10}\right)} \\ F^C_{mr,fineroot} &=& \sum_{j=1} ^{nlevsoi} S^N_{fineroot} \times root_{fr,j} \times br_{mr} \times q_{10}^{\left(\frac{T_{s,j} - T_{frz} - 20}{10}\right)} \end{eqnarray} \]

\[ \begin{equation} mr = F^C_{mr,leaf} + F^C_{mr,livestem} + F^C_{mr,livecroot} + F^C_{mr,grain} + F^C_{mr,fineroot} \end{equation} \]

1.1.2 Growth Respiration

Growth respiration is calculated as the parameter \(gr_{perc}\), times the total carbon in new growth on a given timestep, based on construction costs for a range of woody and non-woody tissues (Larcher, 1995⁵).

Implemented in subroutine: GrowthResp

\[ \begin{eqnarray} \label{eqn_gr} F^C_{gr,leaf} &=& F^C_{alloc,leaf} \times gr_{perc} \\ F^C_{gr,leaf\_stor} &=& F^C_{alloc,leaf\_stor} \times gr_{perc} \times gr_{pnow} \\ F^C_{gr,froot} &=& F^C_{alloc,froot} \times gr_{perc} \\ F^C_{gr,froot\_stor} &=& F^C_{alloc,froot\_stor} \times gr_{perc} \times gr_{pnow} \\ F^C_{gr,livestem} &=& F^C_{alloc,livestem} \times gr_{perc} \\ F^C_{gr,livestem\_stor} &=& F^C_{alloc,livestem\_stor} \times gr_{perc} \times gr_{pnow} \\ F^C_{gr,deadstem} &=& F^C_{alloc,deadstem} \times gr_{perc} \\ F^C_{gr,deadstem\_stor} &=& F^C_{alloc,deadstem\_stor} \times gr_{perc} \times gr_{pnow} \\ F^C_{gr,livecroot} &=& F^C_{alloc,livecroot} \times gr_{perc} \\ F^C_{gr,livecroot\_stor} &=& F^C_{alloc,livecroot\_stor} \times gr_{perc} \times gr_{pnow} \\ F^C_{gr,deadcroot} &=& F^C_{alloc,deadcroot} \times gr_{perc} \\ F^C_{gr,deadcroot\_stor} &=& F^C_{alloc,deadcroot\_stor} \times gr_{perc} \times gr_{pnow} \\ F^C_{gr,grain} &=& F^C_{alloc,grain} \times gr_{perc} \\ F^C_{gr,grain\_stor} &=& F^C_{alloc,grain\_stor} \times gr_{perc} \times gr_{pnow} \\ \end{eqnarray} \]

Parameter \(gr_{pnow}\) is currently set to 1.0. This parameter could be changed to a smaller value to transfer some portion (1 - \(gr_{pnow}\)) of the growth respiration forward in time to occur at the time of growth display from storage.

1.2 Variable definitions

Symbol	Description	Units	ELM Variable
\(lmr_{sun}\)	sunlit leaf maintenance respiration rate	\(umolCO_{2}~m^{-2}~sec^{-1}\)	`photosyns_vars%lmrsun_patch`
\(lmr_{sha}\)	shaded leaf maintenance respiration rate	\(umolCO_{2}~m^{-2}~sec^{-1}\)	`photosyns_vars%lmrsha_patch`
\(lai_{sun}\)	sunlit projected leaf area index	-	`canopystate_vars%laisun_patch`
\(lai_{sha}\)	shaded projected leaf area index	-	`canopystate_vars%laisha_patch`
\(br_{mr}\)	base rate for maintenance respiration	\(gC~gN^{-1}~sec^{-1}\)	`br_mr`
\(q_{10}\)	temperature sensitivity for maintenance respiration	-	`q10`
\(T_{2m}\)	2 m height surface air temperature	K	`veg_es%t_ref2m`
\(T_{s,j}\)	soil temperature at soil level j	K	`col_es%t_soisno`
\(T_{frz}\)	freezing point of water (273.15 K)	K	`SHR_CONST_TKFRZ`
\(root_{fr,j}\)	fraction of roots in each soil layer	-	`soilstate_vars%rootfr_patch`
\(S^N_{livestem}\)	live stem N	\(gN~m^{-2}\)	`veg_ns%livestemn`
\(S^N_{livecroot}\)	live coarse root N	\(gN~m^{-2}\)	`veg_ns%livecrootn`
\(S^N_{fineroot}\)	fine root N	\(gN~m^{-2}\)	`veg_ns%finerootn`
\(S^N_{grain}\)	grain N	\(gN~m^{-2}\)	`veg_ns%grainn`
\(F^C_{mr,leaf}\)	leaf maintenance respiration	\(gC~m^{-2}~sec^{-1}\)	`veg_cf%leaf_mr`
\(F^C_{mr,livestem}\)	live stem maintenance respiration	\(gC~m^{-2}~sec^{-1}\)	`veg_cf%livestem_mr`
\(F^C_{mr,livecroot}\)	live coarse root maintenance respiration	\(gC~m^{-2}~sec^{-1}\)	`veg_cf%livecroot_mr`
\(F^C_{mr,fineroot}\)	fine root maintenance respiration	\(gC~m^{-2}~sec^{-1}\)	`veg_cf%fineroot_mr`
\(F^C_{mr,grain}\)	crop grain or organs maintenance respiration	\(gC~m^{-2}~sec^{-1}\)	`veg_cf%grain_mr`
\(gr_{perc}\)	growth respiration parameter	-	`grperc`
\(gr_{pnow}\)	growth respiration parameter	-	`grpnow`
\(F^C_{alloc,leaf}\)	allocation to leaf C	\(gC~m^{-2}~sec^{-1}\)	`veg_cf%cpool_to_leafc`
\(F^C_{alloc,leaf\_stor}\)	allocation to leaf C storage	\(gC~m^{-2}~sec^{-1}\)	`veg_cf%cpool_to_leafc_storage`
\(F^C_{alloc,froot}\)	allocation to fine root C	\(gC~m^{-2}~sec^{-1}\)	`veg_cf%cpool_to_frootc`
\(F^C_{alloc,froot\_stor}\)	allocation to fine root C storage	\(gC~m^{-2}~sec^{-1}\)	`veg_cf%cpool_to_frootc_storage`
\(F^C_{alloc,livestem}\)	allocation to live stem C	\(gC~m^{-2}~sec^{-1}\)	`veg_cf%cpool_to_livestemc`
\(F^C_{alloc,livestem\_stor}\)	allocation to live stem C storage	\(gC~m^{-2}~sec^{-1}\)	`veg_cf%cpool_to_livestemc_storage`
\(F^C_{alloc,deadstem}\)	allocation to dead stem C	\(gC~m^{-2}~sec^{-1}\)	`veg_cf%cpool_to_deadstemc`
\(F^C_{alloc,deadstem\_stor}\)	allocation to dead stem C storage	\(gC~m^{-2}~sec^{-1}\)	`veg_cf%cpool_to_deadstemc_storage`
\(F^C_{alloc,livecroot}\)	allocation to live coarse root C	\(gC~m^{-2}~sec^{-1}\)	`veg_cf%cpool_to_livecrootc`
\(F^C_{alloc,livecroot\_stor}\)	allocation to live coarse root C storage	\(gC~m^{-2}~sec^{-1}\)	`veg_cf%cpool_to_livecrootc_storage`
\(F^C_{alloc,deadcroot}\)	allocation to dead coarse root C	\(gC~m^{-2}~sec^{-1}\)	`veg_cf%cpool_to_deadcrootc`
\(F^C_{alloc,deadcroot\_stor}\)	allocation to dead coarse root C storage	\(gC~m^{-2}~sec^{-1}\)	`veg_cf%cpool_to_deadcrootc_storage`
\(F^C_{alloc,grain}\)	allocation to grain C for prognostic crop	\(gC~m^{-2}~sec^{-1}\)	`veg_cf%cpool_to_grainc`
\(F^C_{alloc,grain\_stor}\)	allocation to grain C storage for prognostic crop	\(gC~m^{-2}~sec^{-1}\)	`veg_cf%cpool_to_grainc_storage`
\(F^C_{gr,leaf}\)	leaf growth respiration	\(gC~m^{-2}~sec^{-1}\)	`veg_cf%cpool_leaf_gr`
\(F^C_{gr,leaf\_stor}\)	leaf growth respiration to storage	\(gC~m^{-2}~sec^{-1}\)	`veg_cf%cpool_leaf_storage_gr`
\(F^C_{gr,froot}\)	fine root growth respiration	\(gC~m^{-2}~sec^{-1}\)	`veg_cf%cpool_froot_gr`
\(F^C_{gr,froot\_stor}\)	fine root growth respiration to storage	\(gC~m^{-2}~sec^{-1}\)	`veg_cf%cpool_froot_storage_gr`
\(F^C_{gr,livestem}\)	livestem growth respiration	\(gC~m^{-2}~sec^{-1}\)	`veg_cf%cpool_livestem_gr`
\(F^C_{gr,livestem\_stor}\)	livestem growth respiration to storage	\(gC~m^{-2}~sec^{-1}\)	`veg_cf%cpool_livestem_storage_gr`
\(F^C_{gr,deadstem}\)	deadstem growth respiration	\(gC~m^{-2}~sec^{-1}\)	`veg_cf%cpool_deadstem_gr`
\(F^C_{gr,deadstem\_stor}\)	deadstem growth respiration to storage	\(gC~m^{-2}~sec^{-1}\)	`veg_cf%cpool_deadstem_storage_gr`
\(F^C_{gr,livecroot}\)	livecroot growth respiration	\(gC~m^{-2}~sec^{-1}\)	`veg_cf%cpool_livecroot_gr`
\(F^C_{gr,livecroot\_stor}\)	livecroot growth respiration to storage	\(gC~m^{-2}~sec^{-1}\)	`veg_cf%cpool_livecroot_storage_gr`
\(F^C_{gr,deadcroot}\)	deadcroot growth respiration	\(gC~m^{-2}~sec^{-1}\)	`veg_cf%cpool_deadcroot_gr`
\(F^C_{gr,deadcroot\_stor}\)	deadcroot growth respiration to storage	\(gC~m^{-2}~sec^{-1}\)	`veg_cf%cpool_deadcroot_storage_gr`
\(F^C_{gr,grain}\)	grain growth respiration	\(gC~m^{-2}~sec^{-1}\)	`veg_cf%cpool_grain_gr`
\(F^C_{gr,grain\_stor}\)	grain growth respiration to storage	\(gC~m^{-2}~sec^{-1}\)	`veg_cf%cpool_grain_storage_gr`

MB Lavigne and MG Ryan. Growth and maintenance respiration rates of aspen, black spruce and jack pine stems at northern and southern boreas sites. Tree Physiology, 17(8-9):543–551, 1997. doi:10.1093/treephys/17.8-9.543. ↩
Douglas G Sprugel, Michael G Ryan, J Renée Brooks, Kristiina A Vogt, and Timothy A Martin. Respiration from the organ level to the stand. In Resource physiology of conifers, pages 255–299. Elsevier, 1995. doi:10.1016/B978-0-08-092591-2.50013-3. ↩
Michael G Ryan. Effects of climate change on plant respiration. Ecological applications, 1(2):157–167, 1991. doi:10.2307/1941808. ↩
Peter E Thornton and Nan A Rosenbloom. Ecosystem model spin-up: estimating steady state conditions in a coupled terrestrial carbon and nitrogen cycle model. Ecological Modelling, 189(1-2):25–48, 2005. doi:10.1016/j.ecolmodel.2005.04.008. ↩
Walter Larcher. Physiological plant ecology: ecophysiology and stress physiology of functional groups. Springer Science & Business Media, 2003. ↩