New GEM plots in Mato Grosso
The plots are located in the transition zone between Cerrado and Amazon Forest biomes, eastern Mato Grosso, Brazil. One plot was established in a cerrado stricto sensu (savanna) and other in cerradão (savanna forest). The study is conducted at Parque Municipal do Bacaba of the Universidade do Estado de Mato Grosso (UNEMAT), located in Nova Xavantina (14°42′S, 52°21′W) in partnership with Project PELD-Transição Cerrado Floresta-Amazônica (CNPq/Long-term Ecological Projects).
Bacaba park present different vegetation types (cerrado stricto sensu, cerrado rupestre, cerradão and gallery forests) which has been monitored since 1995. The basal area (~21 m2ha-1) and the mean heights (6.4 m) of the cerradão are greater than that of the cerrado stricto sensu (~15 m2ha-1 and 3.7 m). The most important species in cerradão are Hirtella glandulosa, Tachigali vulgaris and Xylopia aromatica, and in the cerrado stricto sensu are Qualea parviflora, Davilla elliptica and Roupala montana. The soils of both areas are acid (pH < 5.0) and dystrophic (Ca2+ < 0.4 cmolc kg-1) with high concentration of exchangeable aluminium (Al3+ > 1.3 cmolc kg-1). The soil fertility do not differ between the aareas. However, the cerradão soil showed higher percentages of clay than the cerrado at all depths up to 2 m, which could result in a higher availability of water throughout the year for the trees. The mean annual temperature is around 24.4°C and the mean annual rainfall is 1600 mm, with the dry season between May and September.
The fieldwork is leaded by Ben Hur Marimon-Junior, Beatriz Schwantes Marimon, Amintas Nazareth Rossete and Ricardo Keichi Umetsu (UNEMAT). The research goals are to understand the dynamic processes involved in the characterization and functioning of ecosystems in the transition between Cerrado and Amazon forest. We will install measurements for below-ground, above-ground NPP monitoring and also CO2 efflux measurements.
We are monitoring: litterfall, titter bag decomposition and release of nutrients, litter layer, soil moisture, soil density, penetrability and infiltrability.
We will install: ingrowth cores, total and component of soil CO2 efflux, stem CO2 efflux, foliage (leaf area index, LAI), dendrometers and coarse woody debris.
Hi Tobby,
Thanks again.
What exactly there will be in Pisac next month?
Best,
Jhon
Dear Jhon,
Apologies for taking a while to reply: I had to check on a few things. Some answers:
"stemlength" is clearly described in the RAINFOR-GEM manual section 1.5 where I put a photo I took of a tree at Wayqecha: it is the length from the base to point A (not B or C) on that photo.
How to calculate aboveground NPP: this is not described in the manual, but briefly described either in Yadvinder's 2009 paper http://www.geog.ox.ac.uk/~ymalhi/publications/Publications2009/2009-gcb-comp-assess-of-carbon-product.pdf or in the Plant Ecology & Diversity papers coming out just now (which I'm sure will be posted on GEM within a week or two).
I am actually working on another paper just now describing these calculations in detail and how exactly to account for branch turnover and other terms (leading on from the Plant Ecology & Diversity papers). This paper isn't finished yet but I should have it complete before the Pisac meeting.
If you will be at Pisac next month perhaps we can talk about this some more?
Best,
Toby
Hi Toby,
Nice explanation. Thanks a lot.
Regarding the topic I still have son questions:
What exactly means stemlength? The vertical distance between the top of the main branch (following the stem) and the ground?
If I have values of canopy NPP (calculated of annual litterfall) and woody NPP (calculated with Chave et al. (2005) using stemlegth, diameter and wood density), how we should calculate the above ground NPP? Should I add the two values or only consider woody NPP as above ground NPP?
Cheers,
Jhon
Hi Jhon,
Thanks for your feedback: this is all a bit of a tricky area. Just to be 100% clear, let's define some terms:
RHEIGHT = "Height" as measured in the RAINFOR protocols, which is really stemlength because that is what is most relevant for biomass estimation.
VHEIGHT = Vertical height to crown top, which for a leaning tree will be less than RHEIGHT. Chave's papers talk about "total tree height" so his H is technically VHEIGHT (and for Larjavaara and Muller-Landau too).
AGLB = AboveGround Live Biomass INCLUDING both stem and branches.
In most papers this is the same as AGB ("AboveGround Biomass", e.g. Chave et al. 2005) but I think it's clearer to say "live" to remind us that coarse woody debris and leaf litter are excluded from this (Chave's paper never mentions litter or CWD but because he talks about the AGB "of a tree" we know litter and CWD were excluded). It's debatable whether live canopy leaves were included in Chave's AGB, but let's assume that they were (the leaves are a negliible component of AGLB anyway so this doesn't matter too much).
OK: so the Chave et al. (2005) paper talked about estimating AGLB from diameter data and VHEIGHT. Because we know that Chave worked almost entirely in lowland forests with only a very small number of leaning trees, it's fair to assume that his VHEIGHT was approximately the same as his RHEIGHT in those study forests.
In a cloud forest context where there are many leaning trees, it's better to use those Chave allometries and substitute H=RHEIGHT not H=VHEIGHT because otherwise AGLB is going to be underestimated.
Does all that make sense?
Best,
Toby
PS. Chave et al. (2005) is the Oecologia paper of Jerome Chave that is available online for free at http://www.winrock.org/ecosystems/files/Chave_et_al-2005.pdf
Hi Toby,
I am confused about this. Which height we should use for height-based allometric equations as Chave (2005)? In that way, what we estimate with this equation: above ground biomass including canopy and stem biomass or only stem biomass?
I'd reallye apreciate if you could help me to understand this.
Best,
Jhon