从植被类型、植被物候、气候因子时滞效应等方面研究 2001 年以来河北山区归一化植被指数（normalized difference?vegetation?index，NDVI）演变规律，并将气候因子时滞效应引入多元线性回归方法中，识别气候因子和人 类活动对河北山区 NDVI 演变的贡献。结果表明：2001—2022 年河北山区 NDVI 呈持续增长趋势，平均增速为 0.003?7/a，其中乔木林、灌木林和草地 3 种植被类型增速分别为 0.003?5/a、0.004?0/a 和 0.003?8/a；受气候变化影响， 河北山区植被生长季变长，生长季开始时间平均提前 9?d，而生长季结束时间仅提前 1?d；降水对植被 NDVI 的影响 主要发生在当月，而气温和潜在蒸散发对植被 NDVI 的影响存在 1 个月的滞后性，考虑气候因子的时滞效应后，气 候变化和人类活动对河北山区 NDVI 演变的贡献分别为 39% 和 61%，与不考虑气候因子时滞效应对比，多元线性 回归的决定系数由 0.80 提高到 0.87。人工水保措施是河北山区植被 NDVI 增长的主导因素，对快速改善山区生 态环境至关重要，同时 2001 年以来降水、气温等气候因素也有利于植被恢复，对植被条件较好的区域，应以自然 恢复为主，实现自然条件下的生态平衡。研究结果对优化山区水土保持工作方案，提高植被修复措施效果具有重要意义。

Since ?2000, ?large-scale ?comprehensive ?control ?of ?soil ?and ?water ?loss ?has ?been ?carried ?out ?in ?the mountainous ?areas ?of ?Hebei ?Province. ?Through ?measures ?such ?as ?enclosure ?protection, ?afforestation ?and ?grass planting, ?and ?return ?of ?farmland ?to ?forest, ?the ?ecological ?environment ?in ?the ?mountainous ?areas ?has ?been significantly?improved,?especially?the?vegetation?coverage?in?the?mountainous?areas?has?been?significantly?increased. However, ?the ?current ?research ?has ?not ?systematically ?analyzed ?the ?vegetation ?evolution ?law ?and ?causes ?in ?the mountainous?areas?of?Hebei?Province.?It?was?difficult?to?scientifically?evaluate?the?comprehensive?control?of?soil?and water ?loss ?in ?mountainous ?areas ?of ?Hebei ?Province. ?When ?analyzing ?the ?causes ?of ?vegetation ?evolution, ?the traditional ?multiple ?linear ?regression ?method ?usually ?adopts ?the ?climate ?variables ?and ?vegetation ?variables corresponding?to?each?month,?and?fails?to?consider?the?"time-lag?effect"?of?climate?factors,?which?may?lead?to underestimating?the?contribution?of?climate?factors. ??????The?evolution?of?NDVI?in?mountainous?areas?of?Hebei?Province?was?systematically?studied?from?the?aspects?of vegetation?types,?vegetation?phenology?and?time?delay?effect?of?climate?factors.?On?this?basis,?a?multiple?linear regression?model?was?established?considering?the?time?delay?effect?of?climate,?which?is?expected?to?answer?the?cause of?NDVI?evolution?more?accurately.?With?precipitation?P,?temperature?T?and?potential?evapotranspiration?PET?as independent ?variables ?and ?vegetation ?NDVI ?as ?dependent ?variables, ?a ?multiple ?linear ?regression ?model ?was constructed ?to ?improve ?the ?traditional ?residual ?analysis ?method, ?and ?the ?effects ?of ?climate ?change ?and ?human activities?on?vegetation?NDVI?changes?were?stripped?away. ??????The?results?showed?that?NDVI?in?mountainous?areas?of?Hebei?showed?a?continuous?growth?trend?from?2001?to 2022,?with?an?average?growth?rate?of?0.0037/a.?The?growth?rates?of?woodland,?shrub?and?grassland?were?0.003?5/a, 0.004?0/a?and?0.003?8/a,?respectively.?Using?the?Mann-Kendall?trend?test?method?to?analyze?the?significance?of NDVI?change,?it?was?found?that?78%?of?the?regions?showed?a?very?significant?increase?trend,?11%?showed?a significant?increase?trend,?and?only?less?than?2%?showed?a?significant?decrease?or?an?extremely?significant?decrease trend,?indicating?that?the?vegetation?recovery?effect?of?the?whole?Hebei?mountain?region?after?2001?was?remarkable. Due?to?the?influence?of?climate?change,?the?growth?period?of?vegetation?in?mountainous?areas?of?Hebei?Province became?longer,?and?the?start?time?of?the?growing?season?was?advanced?by?9?days?on?average,?while?the?end?time?of the?growing?season?was?advanced?by?only?1?day.?SOS?in?Bashang?Plateau,?Yanshan?District?and?Taihang?Mountain area?advanced?by?6?d,?11?d?and?8?d,?and?EOS?advanced?by?2?d,?1?d?and?1?d,?respectively,?meaning?that?the?whole growing?season?increased?by?4?d,?10?d?and?7?d,?respectively.?The?influence?of?precipitation?on?vegetation?NDVI mainly ?occurs ?in ?the ?same ?month, ?while ?the ?influence ?of ?air ?temperature ?and ?potential ?evapotranspiration ?on vegetation?NDVI?has?a?one-month?lag.?After?considering?the?time-lag?effect?of?climate,?the?contribution?of?climate change?and?human?activities?to?the?evolution?of?NDVI?in?mountainous?areas?of?Hebei?is?39%?and?61%,?respectively. After?considering?the?delay?effect?of?climate?factors,?the?coefficient?of?determination?R2?of?multiple?linear?regression increases?from?0.80?to?0.87,?the?root?mean?square?error?decreases?from?0.086?to?0.071,?and?the?average?absolute?error decreases?from?0.108?to?0.090.?The?performance?of?the?improved?regression?model?is?better?than?that?of?the?original model. ??????Since?2000,?the?main?contribution?of?NDVI?growth?in?mountainous?areas?of?Hebei?Province?has?been?artificial vegetation?restoration,?but?at?the?same?time,?the?lengthening?of?growing?season?caused?by?climate?change?is?also?an important?reason.?Studying?and?identifying?the?impact?of?climate?change?and?human?activities?has?important?guiding significance?for?further?rational?and?efficient?soil?and?water?conservation?in?mountainous?areas.