I made a better shader how do i fix[add _Shadow Strength]help???>Sorry that im asking for to much

/\/\old script cast shadows is the issue if turned off its fixed but no shadows. why is it not the receive shadow.btw the leaves are not effected by the sky box?only by mesh?

here is my new script I still want to know how to fix add _Shadow Strength thats why i left it on this new script .I can delete add _Shadow Strength np and it will stay the same.

 Properties {
     _Color ("Main Color", Color) = (1,1,1,1)
     _TranslucencyColor ("Translucency Color", Color) = (0.73,0.85,0.41,1) // (187,219,106,255)
     _Cutoff ("Alpha cutoff", Range(0.25,0.9)) = 0.5
     _TranslucencyViewDependency ("View dependency", Range(0,1)) = 0.5
     _ShadowStrength("Shadow Strength", Range(0,1)) = 1.0
     _MainTex ("Main Texture", 2D) = "white" {  }
     
     // These are here only to provide default values
     _Scale ("Scale", Vector) = (1,1,1,1)
     _SquashAmount ("Squash", Float) = 1
 }
 
 SubShader { 
         UsePass "VertexLit/SHADOWCOLLECTOR"
         UsePass "VertexLit/SHADOWCASTER"
     Tags {
         "Queue"="Transparent-99"
         "IgnoreProjector"="True"
         "RenderType" = "TreeTransparentCutout"
     }
     LOD 200
     Cull Off
         
     Pass {
         Tags { "LightMode" = "Always" }
         Name "Always"
 
     CGPROGRAM
         #include "TreeVertexLit.cginc"
 
         #pragma vertex VertexLeaf
         #pragma fragment FragmentLeaf
         #pragma exclude_renderers flash
         #pragma multi_compile_fwdbase nolightmap
         
         sampler2D _MainTex;
         float4 _MainTex_ST;
 
         fixed _Cutoff;
         sampler2D _ShadowMapTexture;
 
         struct v2f_leaf {
             float4 pos : SV_POSITION;
             fixed4 diffuse : COLOR0;
         #if defined(SHADOWS_SCREEN)
             fixed4 mainLight : COLOR1;
         #endif
             float2 uv : TEXCOORD0;
         #if defined(SHADOWS_SCREEN)
             float4 screenPos : TEXCOORD1;
         #endif
         };
 
         v2f_leaf VertexLeaf (appdata_full v)
         {
             v2f_leaf o;
             TreeVertLeaf(v);
             o.pos = mul(UNITY_MATRIX_MVP, v.vertex);
 
             fixed ao = v.color.a;
             ao += 0.1; ao = saturate(ao * ao * ao); // emphasize AO
                         
             fixed3 color = v.color.rgb * _Color.rgb * ao;
             
             float3 worldN = mul ((float3x3)_Object2World, SCALED_NORMAL);
 
             fixed4 mainLight;
             mainLight.rgb = ShadeTranslucentMainLight (v.vertex, worldN) * color;
             mainLight.a = v.color.a;
             o.diffuse.rgb = ShadeTranslucentLights (v.vertex, worldN) * color;
             o.diffuse.a = 1;
         #if defined(SHADOWS_SCREEN)
             o.mainLight = mainLight;
             o.screenPos = ComputeScreenPos (o.pos);
         #else
             o.diffuse *= 0.5;
             o.diffuse += mainLight;
         #endif            
             o.uv = TRANSFORM_TEX(v.texcoord, _MainTex);
             return o;
         }
 
         fixed4 FragmentLeaf (v2f_leaf IN) : COLOR
         {
             fixed4 albedo = tex2D(_MainTex, IN.uv);
             fixed alpha = albedo.a;
             clip (alpha - _Cutoff);
 
         #if defined(SHADOWS_SCREEN)
             half4 light = IN.mainLight;
             half atten = tex2Dproj(_ShadowMapTexture, UNITY_PROJ_COORD(IN.screenPos)).r;
             light.rgb *= lerp(2.5, 2.5*atten, _ShadowStrength);
             light.rgb += IN.diffuse.rgb;
         #else
             half4 light = IN.diffuse;
             light.rgb *= 2.0;
         #endif
 
             return fixed4 (albedo.rgb * light, 0.0);
         }
 
     ENDCG
     }
 }
 
 FallBack Off
 }