Tool Name	Tree Growth Season
Tool ID	11
Library ID	climate_tools
Version	1.0
Author(s)	O.Conrad, L.Landschreiber (c) 2016

Please cite SAGA whenever you use it for your publications:

Description

The 'Tree Growth Season' tool estimates the potential number of days suitable for tree growth as well as the average temperature for these days. The estimation needs monthly data of mean, minimum, and maximum temperature and precipitation. Internally a soil water balance model is run on a daily basis. Using the given thresholds a relative tree line height can optionally be estimated.

References

Karger, D.N., Kessler, M., Conrad, O., Weigelt, P., Kreft, H., König, C., Zimmermann, N.E. (2019): Why tree lines are lower on islands - Climatic and biogeographic effects hold the answer. Global Ecol. Biogeogr., 00:1-12. doi:10.1111/geb.12897

Paulsen, J. / Körner, C. (2014): A climate-based model to predict potential treeline position around the globe. Alpine Botany, 124:1, 1-12. doi:10.1007/s00035-014-0124-0

Parameters

Name	Type	Identifier	Description	Constraints
Input
Mean Temperature	grid list, input	T	Monthly averages of daily mean temperature (12 grids, January to December) [°C]
Minimum Temperature	grid list, input	TMIN	Monthly averages of daily minimum temperature (12 grids, January to December) [°C]
Maximum Temperature	grid list, input	TMAX	Monthly averages of daily maximum temperature (12 grids, January to December) [°C]
Precipitation	grid list, input	P	Monthly sums of precipitation (12 grids, January to December) [mm / m²]
Soil Water Capacity of Profile	grid, input, optional	SWC	Total soil water capacity (mm H₂O).
Output
Mean Temperature	grid, output	SMT	Mean temperature of the growing season.
Precipitation Sum	grid, output, optional	SMP	Precipitation sum of the growing season.
Length	grid, output	LGS	Number of days of the growing season.
First Growing Day	grid, output, optional	FIRST	First growing day of the year (1-365).
Last Growing Day	grid, output, optional	LAST	Last degree day of the year (1-365).
Tree Line Height	grid, output, optional	TLH	Estimated relative tree line height.
Options
Default	floating point number	SWC_DEFAULT	default value if no grid has been selected	Minimum: 0.000000 Default: 220
Top Soil Water Capacity	floating point number	SWC_SURFACE		Minimum: 0.000000 Default: 10
Transpiration Resistance	floating point number	SW1_RESIST		Minimum: 0.010000 Default: 1
Default Latitude	floating point number	LAT_DEF		Minimum: -90.000000 Maximum: 90.000000 Default: 0
Threshold Temperature	floating point number	DT_MIN	Threshold temperature (C) that constrains the growing season.	Default: 0.9
Minimum Soil Water Content (Percent)	floating point number	SW_MIN		Minimum: 0.000000 Default: 2
Minimum Length	integer number	LGS_MIN	Minimum length (days) of the growing season.	Minimum: 1 Default: 94
Minimum Mean Temperature	floating point number	SMT_MIN	Minimum mean temperature (Celsius) for all days of the growing season.	Default: 6.4
Maximum Tree Line Height Difference	floating point number	TLH_MAX_DIFF		Minimum: 0.000000 Default: 3000