As per your concern I will let you know UPSC, Indian Forest Service Exam details and will also let you know 2015 cut off marks.

Here is the cut off
Minimum qualifying standards/marks approved at the Written Part of the Indian Forest Service Examination-2015
S No Category Marks out of 1400
1 General 483
2 OBC 447
3 SC 393
4 ST 398
5 PH2 361
6 PH3 311

Marks secured by the last finally recommended candidate of Indian Forest Service Examination-2015:-
S No Category Marks out of 1400
1 General 736
2 OBC 682
3 SC 613
4 ST 642
5 PH2 608
6 PH3 575

Eligibility
Nationality:
A candidate must be
(a) a citizen of India, or
(b) a subject of Nepal, or
(c) a subject of Bhutan, or
(d) a Tibetan refugee


Educational Qualification:
Candidate should hold a Bachelor’s degree with at least one of the subjects namely, Animal Husbandry & Veterinary Science, Botany, Chemistry, Geology, Mathematics, Physics, Statistics and Zoology or a Bachelor’s degree in Agriculture or Forestry or Engineering of a recognised university or equivalent.

Candidates appearing at their degree examination (with prescribed subjects) can also compete. If they qualify on the result of the written part of the examination, they will have to submit the proof of passing the required examination alongwith their detailed application form to be filled in at that stage.

Age Limit :
Age of a candidate should be minimum 21 years and maximum 30 years

Syllabus
Part: A – IFS Preliminary Examination Syllabus

Paper- I: General Knowledge
Current Event of National and International importance.
History of India and Indian National Movement.
Indian and world Geography.
Indian polity and Governance.
Economic and social Development.
General Science.
General Issues on Environmental Ecology, Bio-Diversity and Climate Change.

Paper – II: General Studies
Comprehension.
Interpersonal Skills including Communication Skills.
Logical Reasoning and Analytical Ability.
Decision Making and Problem Solving.
General Mental Ability.
Basic Numeracy, Data Interpretation.

General English Syllabus
The English paper would consist of an essay and passages to write the summary
The standard level of papers in General English and General Knowledge are for a Science or Engineering graduate of an Indian University.
Other questions are to test general understanding of English and everyday use of words.

Optional subjects
Agriculture.
Agricultural Engineering.
Animal Husbandry & Veterinary Science.
Botany.
Chemistry.
Chemical Engineering.
Civil Engineering.
Forestry.
Geology.
Mathematics.
Mechanical Engineering.
Physics.
Statistics.
Zoology.