## 1 Introduction  
The forest ecosystem as an important natural resource provides valuable ecological and socio-economic functions to society, and its changes can influence public health [1, 2]. Through the exchange of energy and water vapor between land surfaces and the atmosphere, [PERSON] _et al._[3] found that only 5 km\({}^{2}\) of deforestation could cause a significant warming in the climate. Further induced climate changes can alter the risk of public exposure to extreme weather [4, 5], climate related diseases and allergenic pollen. Recent studies have also documented the close correlations between the quantity and spatial distribution of pollen with climate [6], as well as of nephropathia epidemica with forest phenology [7].  
Vegetation phenology examines the life-cycle phases of plants, such as the timing of leaf unfolding, flowering and leaf fall, in relation with environmental parameters. The shifts of plant phenology are closely linked to climate change, especially with temperature in mid-high latitudes [8, 9]. Using field observations at the species level, [PERSON] _et al._[10] reported that a 1 \({}^{\circ}\)C increase in late winter and spring temperature has induced 5-6 days' advance in the the growing season beginning date in China. [PERSON] _et al._[11] also found a close relationship between temperature and flowering duration of olive trees. With satellite-based observations, [PERSON] _et al._[12] indicated that an extension of the growing season in Eurasia and America was consistent with a warming climate. Although the effects of temperature change on plant phenology have been well documented [13], few studies have explored the sensitivity of phenological responses to temperature gradients related to elevation [14]. For the correlation of disease transmission and elevation [15], phenology changes at different elevation gradients may vary the influence on the public, therefore, studies on spatio-temporal forest dynamics, especially characteristics related to public health, are crucial to assess the implications of any future environmental changes.  
The Khingan Mountain region is the largest and northernmost forested area in China, and it is also the most important and typical natural foci of tick-borne encephalitis (TBE) [16], accounting for more than 90% of the whole country's incidence [17]. TBE is a zoonotic and potentially fatal disease and the causal virus parasitizes common rodent species which preferably inhabit deciduous forests [17]. In addition, the Khingan Mountains are located in the transitional zone between boreal and temperate forests that are more sensitive to climate change. Over the past several decades, this region has experienced a great increase in temperature, and its warming amplitude was much higher than the average level in China [18]. Based on these backgrounds, this study examined the dynamics of deciduous broadleaf forest (DBF) growth, and its phenology response to temperature change during 2001-2009. The objectives of this study were threefold: (1) to investigate spatio-temporal patterns of DBF growth in Khingan Mountains; (2) to quantitatively evaluate the effects of temperature change on DBF phenology; (3) to explore the sensitivity of phenology response to temperature gradients in relation to elevation. This study will improve our understanding of the influences of climate change on montane ecosystems and also help to assess the effects of future environmental changes on public health.