Yes, It has some definite role. Afforestation, C-sequestration and soil quality all three are very much inter-related. C-sequestration potential of several tree sp. are varied. I request you to refer some good papers published in journals like 'Agriculture, Ecosystems, Environment', 'European Journal of Forest Research', 'Agroforestry Systems' as this is a current topic of research for natural resource management scientists.

There are lots of examples where tree species are found influencing the C sequestration, specially in fragile habitats like Himalayas where Quercus has been instrumental in sustaining other vegetation through C sequestering

[J. S. Singh, S. P. S. (1987). Forest Vegetation of the Himalaya. [Journal Article]. Botanical Review, 53(1), 80-192. doi: 10.1007/BF02858183]

further the soil quality has been also influencing factor in determining the vegetation, the soil pH, EC texture are well known factors responsible in vegetational gradients through out ecosystems, having constrains of multiscale environmental variables including hydration, temperature long with zoo-anthropogenic factors.............!

Both, three species and soil properties determine the C dynamics after afforestation. Find below an example in pastures afforestation with different fast growing tree species in temperate areas.

Pérez-Cruzado, C.; Mansilla-Salinero, P.N.; Rodríguez-Soalleiro, R.; Merino, A. (2012). Influence of tree species on carbon sequestration in afforested pastures in a humid temperate region. Plant and Soil. 353:333–353. DOI: 10.1007/s11104-011-1035-0

Yes,

species perform ecosystem function specifically, therefore, each species play specific pattern and mechanism for carbon sequestration, stabilization and mineralization. There are plenty of information available.

Thank you everyone! very good comments and benefit a lot from these answers. I still wondering how to identify the effect from tree species and others, particularly in field site. for example, we can easily found the SOC differences between different forests. However, some of these differences may from different locations, e.g., lower slopes and upper slopes.

Dear Wenjie,

Just focus on site variation, I mean micro site (e.g. slope, patches, undulating, plain surface etc.) you may get differences in soil carbon sequestration. Same species can perform in different magnitude if soil surface is heterogeneous.

thank you Singh, good talk with you. Now I am working on species differences effect on soil properties now. difficult but interesting work!

FIRST, there is no reason to exercise yourself about soil C sequestration because CURRENT CO2 emissions have very little effect on CURRENT climatechange which is largely due to natural causes.....see:

One of many papers showing that CLIMATE WARMING CAUSES INCREASED ATMOSPHERIC CO2 CONCENTRATIONS suggests  that the IPCC thesis and the assumptions of Global Climate Models ----------- that that assume CLIMATE WARMING

IS CAUSEDBY ATMOSPHERIC CO2 CONCENTRATIONS ----------------- are in serious error.... see: 

http://www.clim-past.net/8/1213/2012/cp-8-1213-2012.html

The IPCC thesis and the assumptions of Global Climate Models that that assume that

CLIMATE WARMING IS CAUSED BY  INCREASED ATMOSPHERIC CO2 CONCENTRATIONS ..........has been the basis for taxpayer funded and enormously misguided government policies and regulations designed to curb human emissions of CO2.

 ----------------------------------------------------------------------------

QUOTING from the FULL TEXT of the paper (with somewhat 'iffy' English) concerning the dominance of the Sun's influence on the Earth's CYCLICAL warming and cooling ................. available at:

 http://www.doiserbia.nb.rs/Article.aspx?id=0354-98361500018A&AspxAutoDetectCookieSupport=1#.VRbMQPnF-ah

"The start of the Grand Minimum of TSI is anticipated approximately in cycle 27±1 approximately in 2043±11 and the beginning of the phase of deep cooling of the 19th Little Ice Age (of the Maunder Minimum type) in the past 7,500 years approximately in 2060±11, with possible duration of 45-65 years "

"The Sun is controlling and practically totally determining the mechanism of quasi-bicentennial cyclic alternations of climate changes from warming to Little Ice Age and set corresponding time-scales for practically all physical processes taking place in the Sun-Earth system. The current long practically stable levels of World Ocean and of temperature additionally reflects the current state of global warming during past 17 years, which are under the direct control of the quasi-bicentennial decrease of TSI. Approximately in the end of 2014 we begin the descent into 19th Little Ice Age in the past 7,500 years " 

Peter Salonius