**3.2 Interannual variation of high temperature days inside and outside shelterbelt**

The number of high temperature days (maximum temperature ≥ 35°C) inside and outside shelterbelt from 2012 to 2018 showed a fluctuating upward trend, and the number of high temperature days outside shelterbelt was significantly higher than that inside shelterbelt (**Figure 3**). The annual average high temperature days was 22 days outside shelterbelt, and it was 6 days inside shelterbelt. The number of high temperature days was the most, with 34 days and 17 days inside and outside shelterbelt in 2017, and the fewest high temperature days in 2012 and 2015, with 11 days and 1 days inside and outside shelterbelt, respectively. It can be seen from **Figure 4** that the high temperature days were 43 days and 154 days, the average


*Deserts and Desertification*

**Table 1.**

*Annual mean of meteorological factors inside and outside shelterbelt.*

#### *Ecological Effects of Oasis Shelterbelts in Ulan Buh Desert DOI: http://dx.doi.org/10.5772/intechopen.98679*

maximum temperature were 36.30°C and 36.54°C, whereas the highest temperature fluctuated between 35 ~ 39.5°C and 35 ~ 43.3°C respectively inside and outside shelterbelt from 2012 to 2018. The average maximum temperature outside shelterbelt was 0.66% higher than that inside shelterbelt, but the highest temperature outside shelterbelt was 9.62% higher than that inside shelterbelt. The high temperature days were concentrated from June to August inside and outside shelterbelt, which was also the growing season of plants. The research results showed that oasis shelterbelt

**Figure 3.** *Annual high temperature days inside and outside shelterbelt.*

**Figure 4.** *The distribution characteristics of high temperature inside and outside shelterbelt.*

has a good protection effect against extreme weather, it also can protect crops from high temperature damage inside shelterbelts and play a vital role in plant growth and increase crop yields.
